Abstract:
The presence of a child restraint seat on a vehicle seat is detected by a child restraint seat anchor that is movable from a first position to a second position when a strap from the child restraint seat is coupled to the anchor. In accordance with the preferred embodiment, the movable anchor is slidably mounted in a housing and slides against the bias of at least one spring when the child restraint seat is coupled thereto. A micro switch is activated upon the moveable anchor sliding from the first position to the second position to cause an air bag controller to either deactivate or slow deployment of an air bag when the child seat is present.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to child restraint seat anchors with integrated child seat detectors. 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 either disable an air bag, or to slow the deployment speed of the air bag. 
     BACKGROUND OF THE INVENTION 
     A child being carried in a child restraint seat can be subjected to relatively high impact forces upon deployment of an air bag against the child, whether that air bag is a front air bag or a 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. 
     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 front 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 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, which results 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 
     The present invention is directed to an anchor device for child restraint seats that detects whether a child restraint seat is attached to a vehicle seat. The anchor device comprises a housing adapted to be fixed to the vehicle seat and a movable anchor having coupler and mounting portions, the coupler portion adapted to couple with a coupler on the child seat and the mounting portion being received in the housing. The movable anchor is shiftable within the housing from a first position, indicating that a child seat is not attached to the vehicle seat, to a second position indicating that a child seat is attached to the vehicle seat. At least one spring urges the movable anchor to the first position. A first stop is engaged by the movable anchor when the movable anchor is in the first position and a second stop is engageable by the movable anchor when the movable anchor has shifted to the second position. When engaged by the movable anchor, the second stop transfers force applied by the coupler of the child restraint seat to the vehicle seat. A switch is an operative association with the movable anchor and is adapted to connect to an air bag to disable deployment of the air bag, or reduce the speed of the air bag upon the movable anchor being moved to the second position, indicating presence of the child restraint seat. 
     In another aspect of the invention the movable anchor positively engages the second stop upon shifting to the second position. 
     In a further aspect of the invention, the switch is a normally open switch which is closed upon the movable anchor being shifted to the second position. 
     In still a further aspect of the invention the housing includes a chamber having an opening though a front wall, through which opening the coupler portion of the movable anchor extends. The chamber has a rear wall defining the first stop that is spaced a selected distance from the front wall, the front wall defining the second stop. 
     In another aspect, the invention is directed to an arrangement for attaching a child restraint seat to a frame of a seat back of a vehicle seat, wherein the arrangement comprises a pair of child seat anchors positioned in spaced relation to one another on the frame of the seat back. At least one of the anchors is a movable anchor disposed in a housing fixed to the seat back and being shiftable between a first position, indicating that a child seat is not attached, and a second position, indicating that a child seat is attached. At least one spring is disposed between the housing and the movable anchor for urging the movable anchor to the first position. A switch in operable association with the movable anchor is adapted for connection to an air bag to disable the deployment of the air bag or to modify deployment speed of the air bag upon the movable anchor being moved to the second position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG. 1  is a side view showing a forward facing child restraint seat attached to a front vehicle seat by utilizing a mounting anchor configured in accordance with the principles of the present invention; 
         FIG. 2  is a side view showing a rearwardly facing child restraint seat attached to a front vehicle seat by utilizing a mounting anchor configured in accordance with the principles of the present invention; 
         FIG. 3  is a perspective view, partially cut away, of a front vehicle seat modified in accordance with the principles of the present invention to anchor the child seats of  FIGS. 1 and 2 ; 
         FIG. 4  is a top view, partially in elevation, of a first embodiment of the invention illustrating the position of a movable anchor, prior to attaching the child seat thereto; 
         FIG. 5  is a view similar to  FIG. 4 , but showing a position of the movable anchor after attachment to the child seat thereto; 
         FIG. 6  is an isolated perspective view of an unattached movable anchor configured according to the present invention; 
         FIG. 7  is a top elevation of a second embodiment of an anchor configured in accordance with the principles of the present invention, and 
         FIG. 8  is a perspective view of a third embodiment of an anchor configured in accordance with the principles of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     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 rigid frame  14  is a cross bar  24 , which has fixed thereto anchors  25  and  26  having coupling portions  27  and  28  to which a child restraint seat  30  is attached. 
     A child restraint seat  30  includes 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  34  and  35  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 . 
     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 child restraint seat  30  is an existing configuration, however the principles of the present invention may apply to other child restraint seat configurations. Only if a vehicle air bag is disabled should one consider mounting a child restraint seat  30  facing rearwardly as shown in  FIG. 2 . The arrangement according to the present invention increases the likelihood that air bags are in fact disabled. As is seen in  FIG. 1 , 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 seat  10  or fixed to the vehicle frame supporting the floor  16  at a location behind the seat anchors  25  and  26 . 
     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 another by a distance  44 . In accordance with a preferred embodiment of the present invention, the cross bar  24  which is part of the frame  20  extends between the frame members  41  and  42  at lower ends of the frame members and is fixed at opposite ends  47  and  48  thereto. The anchors  25  and  26 , to which the hooked couplers  34  and  35  of the child restraint seat  30  are attached via the anchor loops formed by the coupling portions  27  and  28 , are mounted on the cross bar  24  proximate the opposite ends  47  and  48  thereof. In accordance with the present invention, as the straps  31  and  32  are tightened by pulling the ends  39  and  40  of the straps, at least one of the anchors  25  or  26  move from a first position to a second position. The straps  31  and  32  need not be shortened if the straps are of a length to begin with that applies tension to the anchors  25  and  26  when the hooked couplers  34  and  35  are attached. 
     Referring now to  FIGS. 4 and 5 , it is seen in a first embodiment of the invention tat at least one of the anchors, preferably the outboard anchor  25 , is an active anchor having a position sensor switch  52  therein which detects the presence of a child seat coupler hook  34  attached to its anchor loop  27 . Upon detecting the presence of the hooked coupler  34 , the position sensor switch  52  transmits a signal over a line  53  to an air bag controller circuit  56  that either disables an air bag  58  or reduces the inflation speed of the air bag. The sensor switch  52  only detects the presence of a child restraint seat  30  and thus operates independently of the presence of an occupant in the child seat. 
     The active anchor  25 , illustrated in  FIGS. 4 and 5 , represents a preferred embodiment of an active anchor, wherein a housing  60  having a pair of bolt holes  61  and  62  is secured to the cross beam  24  of the vehicle seat back  14  by bolts  63  and  64  which pass through the bolt holes  61  and  62 . The housing  60  has a chamber  66  therein having a rear wall  68  and a front wall  70 . The front wall  70  has a pair of openings  72  and  74  therethrough which are separated by a front wall portion  76 . The front wall  70  defines a pair of shoulders  78  and  80  while the front wall portion  76  has a reduced thickness and an internally facing surface  82 . While only the movable anchor  25  is shown as active, the anchor  26  could also be made active by having the configuration of movable anchor  25 . 
     The coupling portion  27  of the movable anchor  25 , which is in the form of a loop, projects through the openings  72  and  74  in the front wall  70  and has a cross bar  83  which defines the back surface of an opening  84  forming the loop of the coupling portion. The cross bar  83  also has a rear surface  85 , which is preferably spaced from the intermediate wall portion  76 . 
     Extending through the openings  72  and  74  and the front wall  70  is a mounting portion  88  of the movable anchor  25 . The mounting portion  88  has a pair of laterally projecting shoulders  89  and  90  positioned opposite the stop surfaces  78  and  80 , respectively, which are spaced by gaps  91  and  92  from the shoulders  89  and  90 , respectively. 
     The mounting portion  88  of the movable lug  25  has a recess  93  therein which receives the intermediate wall portion  76 , a pair of coil springs  94  and  95 , as well as the switch  52 . The coil springs  94  and  95  bear against a rear wall  96  of the recess  93  and against the rear surface  82  of the intermediate portion  76  of front wall  70 . 
     As is further seen in  FIG. 4 , since the coil springs  94  and  95  are under compression, the coil springs push the mounting portion  88 , and thus the movable anchor  25 , back into engagement with the rear wall  68  of the housing  60 . The springs  94  and  95  are under sufficient compression so that it takes 8 to 15 pounds of force to move the movable anchor  25  against the bias of the springs. Preferably, this force is about 10 pounds. Thus, an impact against the vehicle in which the movable anchor  25  is employed, does not generate sufficient force to overcome the compressive force of the springs  94  and  95 . Consequently, the springs  94  and  95  will hold the movable anchor  25  in the first position of  FIG. 4  during an impact. 
     While in the first position, the shoulders  89  and  90  are separated from the front wall stop surfaces  78  and  80  by the gaps  91  and  92 , while an actuator  99  of the micro switch  52  is spaced from the rear wall  96  of the recess  93  by a second gap  100 . The second gap  100  is narrower than the first gaps  91  and  92  so that when the movable lug  25  moves from the first position of  FIG. 4  to the second position of  FIG. 5 , the rear wall  96  of the recess  93  contacts and pushes the actuator  99  of the switch  52  prior to the shoulders  89  and  90  abutting the stop surface walls  78  and  80 . This ensures that the switch  52  is actuated when the movable anchor  25  is shifted to the second position. The gaps  97  and  98  are in the range of 1 to 4 mm, preferably about 2 mm; while the gap  100  between the actuator  99  and rear wall  96  of the recess  93  is preferably about 1 mm or less. 
     As is seen in  FIG. 5 , upon attaching the hooked couplers  34  and  35  to the anchors  25  and  26  and tensioning at least the strap  31 , the movable anchor  25  moves from the  FIG. 4  position to the  FIG. 5  position where the switch  52  is actuated while the shoulders  89  and  90  abut the stop walls  78  and  80 . Since the switch  52  operates the air bag controller  56  to disable deployment of the air bag  58 , and the movable anchor  25  is now pressed positively against the first stop surfaces  78  and  80 , an impact will transfer force from the seat  30  through the strap  31  and hooked coupling  34  to the movable anchor  25 . The movable anchor  25  bears against the housing  60  that is anchored to the cross beam  24  in the seat back frame  20 . Thus, the child restraint seat  30  and child therein are restrained without deployment or with reduced speed deployment of the air bag  58 . 
     In the preferred embodiment the micro switch  52  in a first state is normally “off”, i.e., is off in the position of  FIG. 4 , so that it does not continuously draw current when the child restraint seat  30  is not attached to the vehicle seat. The decision to configure micro switch as normally “off” instead of normally “on” in a first state is based on the likelihood that the child seat  30  will not be attached to the front seat  10  for the majority of the time the vehicle is used. Consequently, it is in accordance with the principles of the present invention to have the micro switch  52  normally open or “off” and only closed or “on” when the child restraint seat  30  is mounted on the vehicle seat  10  and attached to at least the movable anchor  25  to move the switch to a second state. 
     The micro switch  52  is preferably arranged in a micro switch assembly, which assembly includes two resistors used for diagnostics in proximity with the micro switch. For example, a resistor of 100 ohms is placed in series with a movable contact within a micro switch  52  while a 1 K resistor is in parallel with the contact. The micro switch  52  can be mechanical, resistive, magnetic, strain sensing, capacitive or any other type of switch effective for the disclosed purpose of closing or opening in response to attachment of the hooked coupler  34  to the movable anchor  25 . 
     As is seen in  FIG. 6 , the movable anchor  25  is a modular unit with a base  110  and a cover  112 . The line  53  to the air bag controller  56  ( FIGS. 4 and 5 ) is configured as a pair of leads  114  and  116  having electrical connectors  118  and  120  that couple with long leads (not shown) from the air bag controller  56 . By configuring the movable anchor  25  as a modular unit, incorporation of the movable anchor  25  in existing designs for vehicle seats is facilitated. 
     Referring now to  FIG. 7 , while the configuration of  FIGS. 4 and 5  is preferred, the movable anchor  25 ′ may have other configurations such as that of  FIG. 7  in which the bolts  63 ′ and  64 ′ are received in slots  105  and  106  disposed in the mounting portion  88 ′ of the movable anchor. In this configuration, first side surfaces  107  and  108  of the bolts  63 ′ and  64 ′ provide the first stop surfaces for the movable anchor  25 ′, while second side surfaces  111  and  112  of the bolts  63 ′ and  64 ′ provide second stop surfaces for the movable anchor  25 ′. This is because the coil springs  94 ′ and  95 ′ urge the movable anchor  25 ′ in a direction into the housing  60 ′. 
     Referring now to  FIG. 8 , there is shown another embodiment of the invention wherein a movable anchor  25 ″ pivots from a first position, in which the child seat  30  is not attached to the movable anchor, to a second position (dotted lines) in which the movable anchor  25 ″ is lifted upon coupling the hooked coupler  34  of the child seat thereto. In the arrangement of  FIG. 8 , the movable anchor  25 ″ is biased to the first solid line position and pivots against the bias of a spring to the dotted line position, the pivoting motion operating a position sensing switch within the housing  60 ″ that disables the air bag. 
     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.