Abstract:
A novel infant child restraint system that includes a base having a height adjustment to allow the base to assume one of a plurality of positions and inclinations when mounted to the vehicle seat. Additionally, in certain embodiments the base is formed to have a recessed knee-receiving area, into which the user can place their knee when tightening the vehicle&#39;s restraint system around the base. The base and car seat are removably attached in interlocking relation using a novel connection mechanism that is not susceptible to premature or improper release due to forces, regardless of the direction of such forces. This mechanism is independent of the car seat handle. Furthermore, this connection mechanism includes a simple manual disconnect or release system, to allow quick removal of the seat from the base.

Description:
This application is a continuation of U.S. patent application Ser. No. 12/971,216 filed Dec. 17, 2010, which claims priority of U.S. Provisional Patent Application Ser. No. 61/288,579, filed Dec. 21, 2009, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Infant child restraint systems are well known in the art. Typically, the infant child restraint system is made up of two parts; an infant car seat and a base into which the infant car seat is mounted. The base is positioned on the seat of a vehicle, such as a car, truck, train or airplane, and secured using the restraint system of the vehicle, or a latch system. For example, a base is typically secured in place on an automobile seat through the use of the vehicle&#39;s seat belt or a latch system. 
     The infant car seat is then attached to the base, typically using one or more connection points. This allows the base to be left secured to the vehicle seat, while only the baby seat is removed. To provide maximum protection to the infant, the infant seat is typically oriented such that when the infant occupies the seat, the infant&#39;s feet are nearest the seat back. 
     There are a number of issues associated with each of these two components. For example, as stated above, the base is typically secured to the vehicle seat via the restraint system. Usually the restraint system consists of a lap belt, which in its operative mode is a horizontally disposed belt that passes across the passenger at the waist. The restraint system also includes a shoulder belt, which in its operative mode is slanted and positioned from the waist of the passenger on one side to the opposite shoulder. Alternatively, a latch system can be employed. 
     In view of its low vertical profile, the base generally must be secured using only the lap and shoulder belt. Given the single axis of restraint, it is important that the weight of the base (with the baby seat) is properly distributed. If the belt crosses the base at an unstable position, it is possible that the base may be able to rotate about this axis of restraint, especially in the case of a sudden change in motion, such as sudden braking or a crash impact. 
     A second issue associated with the base is the need to insure that the base is tightly secured by the vehicle&#39;s restraint system. If the belt is not taut, it is possible that the base (and attached baby seat) can shift forward during a sudden stop or crash impact. 
     Another issue is the variation in slope and position of the vehicle seat onto which the base is placed. For example, some vehicle seats are horizontal, or nearly horizontal. Others, however, are much more sloped. Typically, the inner portion of the seat, where it meets the seat back, will be at a lower height then the outer portion of the seat, where the user&#39;s legs hang from. Therefore, the base, unless it has an adjustment, is positioned at different inclinations, based on the vehicle&#39;s seat. These differences in inclination cause the infant car seat to also be at different inclinations; some of which may not offer sufficient protection for the infant. Height adjustments within the base can be used to minimize this issue. 
     In addition to the above mentioned safety concerns associated with the base, there are also a number associated with the connection of the base to the infant car seat. The connection of the base to the infant car seat has conflicting goals. On the one hand, it is preferable for the seat to be easily disconnected from the base, so that a parent can easily separate the infant car seat from the base and use the disconnected seat as a baby-carrying apparatus. On the other hand, it is imperative that the connection be robust enough that it does not inadvertently disconnect in response to a sudden motion or impact. 
     Therefore, it is important that the connection mechanism between the base and the infant car seat be easily actuated yet robust, even in the presence of sudden, unexpected movements. Some connection mechanisms are optimized to withstand forces in one particular direction. In other words, they are tested to insure no inadvertent disconnections when the seat is forced forward relative to the base. While this is obviously important, this connection must equally withstand forces that tend to push the infant car seat backward, to the left and to the right. 
     While the strength of the connection cannot be compromised, there is a need for a manual disconnect mechanism that is preferably simple and requires little force to operate. This manual disconnect mechanism is preferably operable using a single hand, such that the other hand can be used to hold or support the infant car seat. Additionally, the mechanism should preferably be located in a convenient location, so that the user can readily access the mechanism with minimum inconvenience. 
     In addition to the strength and convenience of the connection mechanism, another important consideration is the location of the mechanism with respect to both the base and the car seat. In some embodiments of the prior art, the connection mechanism includes one point of attachment. In this scenario, the location of that attachment point is critical. If the attachment point is located near one end of the car seat, such as near the feet, it may be possible for the car seat to rotate about this attachment point. For example, a sudden stop may cause the car seat to move relative to the base. If the attachment point is located near the end of the car seat (either the head end or the foot end), the seat can rotate about this point, causing unnecessary motion of the seat and excessive stress on the attachment point and connection mechanism. 
     Some other considerations include the overall weight and strength of the infant car seat, and its ability to be attached to a stroller, or other apparatus. 
     Currently, some of these issues are addressed in a variety of ways, with varying degrees of success. In some cases, the solutions to these issues are expensive, thereby raising the price of the infant child restraint system. It would be beneficial if these issues could be addressed in a safe, convenient and cost effective manner. 
     SUMMARY 
     The problems of the prior art are addressed by a novel infant child restraint system. This system includes a base having a height adjustment to allow the base to assume one of a plurality of positions and inclinations when mounted to the vehicle seat. Additionally, in certain embodiments the base is formed to have a recessed knee-receiving area, into which the user can place their knee when tightening the vehicle&#39;s restraint system around the base. The base is configured not only to be mounted to a vehicle seat, but also to removably receive a child carrier, such as a car seat. 
     The base and car seat are removably attached in interlocking relation using a novel connection mechanism that is not susceptible to premature or improper release due to forces, regardless of the direction of such forces. This mechanism is independent of the car seat handle. Furthermore, this connection mechanism includes a simple manual disconnect or release system, to allow quick removal of the seat from the base. The connection mechanism is positioned at attachment points on the base in such a position such that the seat will not rotate relative to the base in the event of sudden deceleration or impact of the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of the base according to one embodiment of the present invention; 
         FIG. 2  is an exploded view of the base of  FIG. 1 , showing the base plate and the height adjuster; 
         FIG. 3  is an isometric view of the base plate of  FIG. 2 ; 
         FIG. 4  is a bottom view of the base plate of  FIG. 3 ; 
         FIG. 5  is a cross section of the base plate of  FIG. 3 ; 
         FIG. 6  is a front view of the height adjuster of  FIG. 2 ; 
         FIG. 7  is a back view of the height adjuster of  FIG. 2 ; 
         FIG. 8  is an isometric view of the height adjuster of  FIG. 2 ; 
         FIG. 9  is a side view of the height adjuster of  FIG. 2 ; 
         FIG. 10  is a cross section of the base of  FIG. 1  shown at the hinge point of the height adjuster; 
         FIG. 11  shows an infant child restraint system with the height adjuster in a first position; 
         FIG. 12  shows an infant child restraint system with the height adjuster as it transitions from a first position to a second position; 
         FIG. 13  shows an infant child restraint system with the height adjuster as it transitions from a first position to a second position; 
         FIG. 14  shows an infant child restraint system with the height adjuster in a second position; 
         FIG. 15  shows an expanded view of the connection between the height adjuster and the base plate; 
         FIG. 16   a  shows a second embodiment of an infant child restraint system with a height adjuster in a first position; 
         FIG. 16   b  shows a second embodiment of an infant child restraint system with a height adjuster in a second position; 
         FIG. 17  shows the height adjuster of  FIG. 16   a - b;    
         FIG. 18  shows bottom view of the height adjuster of  FIG. 16 ; 
         FIG. 19  shows a perspective view of the infant car seat; 
         FIG. 20  shows a view of the infant car seat of  FIG. 19  with the padding removed to reveal internal elements; 
         FIG. 21  shows a top view of the infant car seat of  FIG. 20 ; 
         FIG. 22  shows an expanded view of one embodiment of the locking mechanism of the infant child restraint system; 
         FIG. 23  shows a cross sectional view of the locking mechanism of  FIG. 22 ; 
         FIG. 24  shows the unlock mechanism of  FIG. 22  in isolation; 
         FIG. 25  shows the unlock mechanism of  FIG. 22  within the infant car seat; 
         FIG. 26  shows an expanded view of the unlock mechanism shown in  FIG. 25 ; 
         FIG. 27  shows another view of the unlock mechanism of  FIG. 22 ; 
         FIG. 28  shows a side view of the connection point; 
         FIG. 29  shows a side view of the connection point; 
         FIG. 30  shows the release handle for the unlock mechanism; 
         FIG. 31  shows a view of the release handle and lip; 
         FIG. 32  shows another view of the release handle and lip; 
         FIG. 33  shows a view of the release handle and upper members of the unlock mechanism; 
         FIG. 34  shows an expanded view of the release handle and upper members; 
         FIG. 35  shows the attachment points between the infant car seat and the base; 
         FIG. 36  shows the handle used with the infant child restraint system; 
         FIG. 37  shows the outside view of right handle; 
         FIG. 38  shows a top view of right handle; 
         FIG. 39  shows a view of the inner edge of the right handle; 
         FIG. 40  shows a top view of the right handle; 
         FIG. 41  shows an expanded view of the handle attachment mechanism of left handle; 
         FIG. 42  shows a top view of the left handle and right handle joined together; 
         FIG. 43  shows a top view of the left handle, right handle and handle cap; 
         FIG. 44  shows an expanded view of one embodiment of the locking mechanism of the infant child restraint system; 
         FIG. 45  shows another view of the locking mechanism of  FIG. 44 ; 
         FIG. 46  is a second embodiment of the hook located on the base; 
         FIG. 47  shows the tab and hook of the second embodiment in the normal locked position; and 
         FIG. 48  shows the tab and hook of the second embodiment in a secondary locked position in the event of an accident. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a side view of the base  10  of the infant child restraint system, in accordance with one embodiment. The base  10  is comprised of two parts, a base plate  100  and a height adjuster  200 . In one embodiment, the base plate is a single molded plastic part. It may be made from polypropylene or other plastic. Similarly, the height adjuster  200  is also a single molded plastic part, made from similar materials. 
       FIG. 2  shows an exploded view of the base  10 , showing the relative sizes and positioning of the base plate  100  and the height adjuster  200 . 
       FIG. 3  shows a perspective view of the base plate  100 . Base plate  100  has two openings  101   a ,  101   b  through which the vehicle&#39;s restraint system can pass. In addition, a belt guide path  105  is positioned between the two openings  101   a ,  101   b  and defines the regions where the vehicle&#39;s seat belt or latch system presses against the base plate  100 . The vehicle&#39;s belt passes through one of the openings  101 , over the belt guide path  105 , and through the second opening  101 . The fastener for the vehicle belt that locks the belt in place may be located outside of the base plate  100 , or between openings  101   a ,  101   b . The base plate  100  also includes an attachment point  110  to which the infant car seat is connected. The placement of the attachment point  110  above the guide path  105  provides a secure location, sandwiched between the belt and the seat back. 
     The base plate  100  also may include one or more grooves  115 , into which contoured edges of the infant car seat (not shown) may rest. Although the seat is not secured to these grooves, the use of these grooves  115  and contours increases the stability of the infant car seat in the base  100 . Optionally, one or more catches  120  may be inserted into the base plate  100 . These catches  120  are located so as to correspond to claws on the infant car seat. In this embodiment, the infant car seat is connected to the base plate  100  at attachment point  110 , as well as at catches  120 . The infant car seat is then pressed in a downward direction so that the clips  120  snap into place, as is described in more detail later. 
     One of the issues cited above is the need to insure that the base  100  is secured tightly by the vehicle&#39;s restraint system. Typically, the base  100  is placed on the vehicle&#39;s seat and the vehicle&#39;s restraint belt is tightened around the base in some manner. As it is critical to maintain tautness, the operator often attempts to push the base downwardly and rearwardly, so as to press it into the junction formed by vehicle&#39;s seat and seat back. Such a process is typically ineffective, and is awkward and inconvenient for the user, resulting in extra length in the belt, thereby allowing the base  10  to move relative to the vehicle seat. 
     Accordingly, in accordance with certain embodiments, base plate  100  includes a molded recess  130  in the general area that is configured to rest on the vehicle&#39;s seat. The recess  130  has an arcuate end  131 , furthest from the front edge  135  of the base  100 . The arcuate end  131  may be semicircular, arced or curvilinear. In some embodiments, the radius of the arc of the arcuate end is designed to be slightly larger than that of a typical bent knee shape. The sides  134  of the recess  130  may be straight and may be parallel to one another, or may extend slightly outwardly going from the arcuate end  131  to the front edge  135 . In another embodiment, the sides  134  may extend inwardly going from the arcuate end  131  to the front edge  135 . 
     The arcuate end  131  transitions to the upper level  140  on the base plate  100  via a sloped surface  132 . This sloped surface is preferably concave up. Similarly, sides  134  transition to a higher level on the base plate  100  via a sloped surface  132 . The sloped surface  132  preferably meets the upper level  140  in an arcuate shape. 
     In operation, the recess  130  and sloped surfaces  134  are configured to accommodate the knee of the operator. The user would place their knee in the recess  130 . They would then use the sloped surface  132  as leverage to drive their knee forward, toward the seat back. Due to the shape of the recess and the sloped surface, the user&#39;s knee is not subjected to any sharp edges, and therefore, the user is able to apply greater downward and forward force. This allows the restraint system to be secured at its tightness point. It is important to note that the recess and sloped walls provide surfaces in two directions for the user. Thus, the recess  130  provides a surface which the user can push downward. Sloped surfaces  132  provide a surface which the user can push forward. This configuration, built to accommodate the general shape of a bent knee, allows maximum force to be exerted. 
       FIG. 4  shows a bottom view of the base plate  100 . In this view, one of the openings  101   a  is visible. The shape of the recess  130  is also visible from the bottom side of the base plate, although this is not a requirement of the design. Near the rear of the base plate, there are two slots  155  (only one shown). These slots are used to accommodate the height adjuster  200 , as will be described in more detail later. A raised tab  150  is also used in conjunction with the height adjuster  200 . 
       FIG. 5  is a cross section of the base plate  100 . This cross section shows the slot  155  that accepts a post on the height adjuster  200 . The tab  150  is also visible. 
       FIG. 6  shows a front view of a first embodiment of the height adjuster  200 . The front surface of the height adjuster is preferably smooth, since in one position, this surface is in contact with the vehicle seat. The height adjuster  200  has a roughly rectangular body  201 , with two arms  205  extending upward. Each arm  205  has a radially inwardly facing post  210 , which mates with slots  155  on the base plate  100 . In another embodiment, the arms may be located closer to the middle of the body  201 , with the posts  210  facing radially outwardly. Small protrusions  215  may be located on the top of each arm  205 , and extend axially therefrom. Although not shown, the bottom surface of the height adjuster  200  is also preferably smooth, as it contacts the vehicle&#39;s seat in one position. 
       FIG. 7  shows a rear view of the height adjuster  200  of  FIG. 6 . The rear surface need not be smooth, as it never contacts the vehicle&#39;s seat. To provide additional strength, the height adjuster  200  may have ribs  220  across the rectangular body  201 . Although spaced axial ribs are shown, the number, spacing, thickness and positioning of the ribs is not particularly limited. If desired, ribs can also be placed within the arms  205 . In addition to posts  210 , two small protrusions  215  are visible on the top of the arms  205 . 
       FIGS. 8 and 9  show two additional views of the height adjuster  200 . The front surface of arms  205  are preferably curved inwardly in the direction from the rectangular body  201  to the top of the adjuster  200 . As will be described in more detail below, the adjuster  200  rotates about the posts  210 . The curved shape of the front of the arms allows this rotation to occur. 
       FIG. 10  shows a cross section of base  10 , with the adjuster  200  in a first, fully extended position. Posts  210  on the adjuster  200  are shown inserted into slots  155  of the base plate  100 . As can be seen in  FIG. 10 , slots  155  are preferably oblong, providing a track in which the posts  210  can travel axially in response to a force applied to the adjuster  200 . It is also seen that the curvature of arms  205  allows them (and the adjuster  200 ) to rotate about the axis defined by the posts, without being impeded by the wall of the base plate  100 . 
       FIG. 11  shows the infant child restraint system with the height adjuster  200  in a second, fully retracted position. As described above, the front surface of the adjuster  200  is preferably smooth as this surface is in contact with the vehicle&#39;s seat. In this second position, the posts  210  are positioned at the lower end of slots  155 . The protrusions  215  may press against the inside wall, forcing it to bow slightly outward. The pressure exerted by the bowed wall in this orientation helps to retain the adjuster  200  in this position. 
       FIG. 12  shows the infant child restraint system as the height adjuster in an intermediate position as it moves from the second, fully retracted position to the first, fully extended position (or vice versa). In this stage of movement, the adjuster  200  is being rotated about the axis defined by the posts  210 . The curvature of the arms allows the adjuster to turn. As this happens, the bottom surface of the adjuster begins to emerge from the base plate  100 . 
       FIG. 13  shows the infant child restraint system as the height adjuster from the second position to the first position. In this stage of movement, the adjuster  200  has been rotated about the axis defined by the posts  210  until its front surface is against the inside wall of the base plate  100 . The bottom surface of the adjuster is now in contact with the vehicle&#39;s seat. 
       FIGS. 14 and 15  show the infant child restraint system in a second position. In this stage, the adjuster is moved upward, such that the posts  210  are against the upper end of the slots  155 . When in this position, tab  150  (also see  FIG. 4 ) is now beyond the rear surface of the adjuster, thereby holding the adjuster in place between the inner wall and the tab  150 . In another embodiment, the adjuster  200  has a corresponding aperture on the top surface of the rectangular body  201 , such that by moving the adjuster  200  upward into the slot  155 , the tab  150  slides into the aperture in the adjuster  200 , thereby holding it in this second position. In both of these embodiments, the tab  150  serves to create a second stable location, whereby the height adjuster cannot move without manual intervention. 
     This embodiment shows an example where the height adjustment is achieved through roughly a 90° rotation of the adjuster  200 . In one embodiment, the adjuster is positioned with its front surface roughly parallel to the vehicle&#39;s seat in one position. In another position, the adjuster is rotated so that the front surface is roughly perpendicular to the vehicle&#39;s seat. Posts in the adjuster and slots in the base plate are but one way to achieve this type and degree of motion. 
       FIGS. 16-18  show a second embodiment of the height adjuster  300 . In this embodiment, the adjuster  300  also has positions.  FIG. 16   a  shows the infant child restraint system in the first position. As can be seen in this figure, the height adjuster  300  has posts  310  located along its outside edges. These posts are inserted into slots  165  in the base plate  100 . As before, the slots  165  are preferably oblong, so that the posts  310  can travel in one direction within the slot. As shown in  FIG. 16   a , the posts  310  are slid forward in slots  165 . 
     Preferably height adjuster  300  extends slightly from the base plate  100  in this first position (as was also shown in  FIG. 11 ). Since the front surface of the height adjuster is smooth, it will not damage the vehicle&#39;s seat. By extending slightly beyond the base plate  100 , the edges of the base plate are not in contact with the seat, allowing them to be less finished. 
       FIG. 16   b  shows the infant child restraint system in a second position. In this position, the height adjuster  300  extends beyond the back of the base plate  100 , thereby raising its height. As shown in  FIG. 17 , in one embodiment, there is a slotted opening  320  in the height adjuster  300 , such that the bottom edge of the base plate  100  rests in the slotted opening  320  in the second position. To allow the adjuster  300  to extend beyond the rear wall, the posts  310  are moved back against the slots  165 . 
     To move between the first position and the second position, the adjuster  300  is first rotated about the axis defined by the posts  310 . This allows the adjuster  300  to extend beyond the bottom of the base plate  100 . When the adjuster  300  has rotated sufficiently, the adjuster  300  is then pulled back toward the rear of the base plate  100 , forcing the posts  310  to slide in the slots  165  from their forward position to the back position. The adjuster  300  is then rotated in the opposite direction until the bottom edge of the base plate  100  enters the slotted openings  320  ( FIG. 17 ) in the adjuster  300 . To return to the first position, these steps are simply performed in reverse. 
       FIG. 17  shows a side view of the adjuster  300  in isolation. Slotted openings  320  exist on the upper portion of the adjuster, and are configured to allow the bottom of base plate  100  to slide therein. Also on the upper portion of the adjuster  300  are the radially extending posts  310 , which slidingly cooperate with the slots  165  in base  100  (see  FIG. 16   b ) to allow the pivotable attachment of the adjuster  300  to the base plate  100 . Although not required by the invention, the lower portion of the adjuster is preferably smooth, as it rests against the vehicle seat. 
       FIG. 18  shows a bottom view of the adjuster  300  in the base plate  100 . The adjuster  300  is in the first, fully extended position in this figure. 
     This embodiment shows an example where the height adjuster rotates less than 90° and uses lateral translation of the posts within the slot to move between the two positions. The embodiment of  FIGS. 16-18  is not to be considering limiting. For example, the height adjuster  300  may be oriented roughly perpendicular to the vehicle&#39;s seat. In one position, the height adjuster does not extend beyond the bottom of the base plate  100 . To move to the second position, the adjuster is moved vertically along an elongated slot. At the bottom of the slot, the adjuster is rotated slightly, so that a slot in the adjuster is engaged by the rear wall of the base plate  100 . 
       FIG. 19  shows the car seat  400 . The car seat  400  has a head end  410 , where the child&#39;s head is placed, and a foot end  420 , with a back support therebetween. When inserted into the base  100 , the foot end  420  is closest to the seat back. This offers maximum protection for an infant, as a sudden stop of the vehicle does not force the infant forward into the restraints. Rather, a sudden stop pushes the baby toward the padding in the infant car seat  400 . The various slits  411  shown in  FIG. 19  are used to adjust the restraints that are used to hold the infant in the car seat (not shown). 
     In certain embodiments, the car seat  400  also includes radially extending connection points  430 , which may serve two purposes. In some embodiments, these connection points  430  snap into notches or recesses  137  in the base  100  (see  FIG. 3 ), which serve as an additional set of attachment points between the car seat  400  and the base  100 . In some embodiments, these connection points may be used to attach the infant car seat into a corresponding stroller or other similar apparatus. The infant seat also comprises a handle  440 . 
       FIG. 20  shows the car seat  400  of  FIG. 19  with the padding and handle removed, revealing the underlying components. The car seat  400  preferably comprises a single hard plastic shell  450 . Suitable materials of construction for the hard shell include polypropylene. 
       FIG. 21  shows a top view of the car seat of  FIG. 20 . In addition to the shell  450 , an unlock mechanism  460  is shown extending from the head end  410  to the foot end  420 . At the foot end  420 , the unlock mechanism  460  attaches to rotatable tabs  470 . As will be explained in more detail later, these tabs  470  rotate when the unlock mechanism  460  is engaged, thereby disconnecting the car seat  400  from the base  100 . The unlock mechanism  460  is preferably located along the outer portion of the shell  450 , so that it is not impeded by the weight of the infant resting on it. In some embodiments, the shell  450  has one or more channels  455  along the outer edge, such that the unlock mechanism  460  sits within the channels  455 . In addition, alignment means, such as alignment pins  457 , are positioned within the channel  455  to hold the unlock mechanism  460  in place. 
       FIG. 22  shows an expanded view of one embodiment of the rotatable tabs  470  and their connection to the unlock mechanism  460 . The tabs  470  are rotatably affixed to the car seat at pivots  472 . The unlock mechanism  460  attaches to the tab via elongated arm  473 . In the locked position, a locking portion  474  of tab  470  is lockingly positioned under metal tab  471 . As can be better seen in  FIG. 23 , the metal tab  471  is attached to the base plate  100 . The upper edge  476  of each metal tab  471  is angled to facilitate the locking process. Below the angled portion  476  is a notched area  477 . A locking portion  474  of the tab  470  is lockingly engaged in this notched area  477  when in the locked position. The locking portion  474  of the tab  470  and the elongated arm  473  are located on opposite sides of the pivot point  472 . In this configuration, an upward movement of the unlock mechanism  460  causes an outward rotation of the locking portion  474  of the tab  470  away from metal tab  471 . The specific shape of the tab  470  can vary, in that the locking portion  474 , the pivot  472  and the elongated arm  473  must all be present, however, their sizes and orientation with respect to each other can vary. Tab  470  can be made from various materials, including but not limited to metal, or hard plastic. Although the tab  471  is preferably metal and is referred to as the metal tab, other material can also be used for its construction. 
     Returning to  FIG. 22 , the locking process will be described. When the car seat  400  is properly positioned about the base  100 , the tabs  470 , and specifically the locking portions  474 , will be aligned with the metal tabs  471 . When the car seat is pushed downward, the tabs  470  press against the angled portions of the metal tabs  471 . These angled portions  476  urge the tabs  470  to rotate away from the metal tab  471 . Note that the tabs  470  necessarily rotate in opposite directions with respect to each other due to the symmetric nature of the design. As the tab  470  rotates, the unlock mechanism  460  (which does not move during the locking process) slides along the elongated arm  473 , thereby offering little resistance to this rotation. Once the car seat has been pressed down far enough, the locking portion  474  of the tab  470  moves past the angled portion  476  and reaches the notch area  477 . A biasing element, such as a spring (not shown), urges the tabs  470  to rotate back, thereby moving the locking portion  474  into the notched area  477 , holding the car seat in place. 
     To disengage the car seat from the base, the user urges the unlock mechanism  460  toward the head end  410 . This action causes the unlock mechanism  460  to pull the elongated arms toward the head end  410 . This causes tabs  470  to rotate about pivots  472  and release the locking portions  474  of the tabs  470  from beneath metal tabs  471 . 
     Since the tabs  470  rotate in opposite directions relative to each other to release the car seat, this locking mechanism is not vulnerable to premature or improper release from forces, regardless of the direction of those forces. Impacts from the side may cause the car seat to move laterally relative to the base. Referring to  FIG. 23 , assume the car seat is forced left relative to the base. This action will tend to push the tab  470  on the left side of the drawing away from the metal tab  471 . However, this action also serves to push the tab  470  on the right side deeper into the notch  477 , thereby continuing to hold the car seat in place. Similarly, a force to the right would cause a reversal of the impact on each tab. Note also that this mechanism is designed to have no susceptibility to front or backward motion, since the tabs cannot be moved in these directions. 
       FIG. 21  shows the car seat with the padding removed, so that the unlock mechanism  460  is visible.  FIG. 24  shows the unlock mechanism  460  outside of the car seat. The unlock mechanism  460  has a release handle  481 , which the user grasps and pulls to engage the mechanism  460 . Attached to the release handle  481  are two upper members  482   a,b . These upper members  482  are enclosed within the head end of the car seat. The upper members  482  attach to two lower members  484   a,b , which are enclosed in the foot end  420 . Between the upper and lower members are the connection points  430 . As described earlier, lower members  484  terminate in a connection to tabs  470 . In some embodiments, the release handle  481  and upper members  482   a,b  are integral, while in other embodiments, these parts are separate components. Similarly, upper members  482   a,b  and lower members  484   a,b  may be integral, or may be separate components. 
       FIGS. 44 and 45  shows a second embodiment of the tab  570 . This tab is similar to tab  470 , with several exceptions. Tab  570 , as seen in  FIGS. 44 and 45 , has an opening  578  near the locking portion  574 . This opening  578  is used in conjunction with the metal tab  571  (see  FIG. 46 ), as will be described below. Similar to tab  470 , tab  570  has an elongated arm  573  which attaches to lower member  484   a,b . The tabs  570  are rotatably affixed to the car seat at pivots  572 . The unlock mechanism  460  attaches to the tab via elongated arm  573 . 
       FIG. 45  shows a perspective view of tab  570 . In this embodiment, tab  570  is not flat, but has a turned up edge  579 . The opening  578  is close to the turned up edge  579 . In other embodiments, the tab is flat, but has an opening  578 . 
       FIG. 46  shows the metal tab  571 . The upper edge  576  of each metal tab  571  is angled to facilitate the locking process. Below the angled portion  576  is a notched area  577 . The locking portion  574  of the tab  570  is lockingly engaged in this notched area  577  when in the locked position. The locking portion  574  of the tab  570  and the elongated arm  573  are located on opposite sides of the pivot point  572 . In this configuration, an upward movement of the unlock mechanism  460  causes an outward rotation of the locking portion  574  of the tab  570  away from metal tab  571 . Metal tab  571  also has a downward projection  581  located at the upper region of the notched area  577 . 
     In normal operation, this downward projecting hook  581  rests on the locking portion  574  of tab  570 , as shown in  FIG. 47 . In this mode, the downward projecting hook  581  does not contact turned up edge  581  or opening  578  in the metal hook  571 . Tab  570  rotates as described above. 
     However, in the event of a collision, it is possible that the tab  570  and metal hook  571  may move relative to each other. For example, in the event of a head-on collision, the two components may move relative to each other. In one embodiment, the hook  571  moves forward (i.e. into the page along direction  585 ), while tab  570  moves in the opposite direction. Without a mechanism to stop this relative motion, the hook and tab may disengage (for example, see  FIG. 22 , where tab  471  is flat). 
     Therefore, in this embodiment, the turned up edge  581  and opening  578  serve as a secondary locking mechanism.  FIG. 48  shows how the tab  570  and the metal hook  571  interlock in the event of relative motion between them. In this embodiment, the downward projection  581  slides into opening  578 . Since metal hook  571  is biased downwardly, the projection  581  moves down and effectively “snaps” into the opening  578 . The turned up edge  579  is simply to insure that the hook  571  does not slide past the tab  570  before the projection  581  catches the opening  578 . In some embodiments, the turned up edge  579  may not be needed. 
       FIG. 25  shows an expanded view of the unlock mechanism  460  near the connection point  430 . As described earlier, the connection point  430  allows the car seat to attach to the stroller or other apparatus that has cooperating notches or recesses  137 .  FIG. 26  shows an expanded view of  FIG. 25 . The upper member  482  connects to a ramped portion  483 . When the upper member  482  is moved upwardly or axially (toward the head end), it brings the ramped portion  483  upward toward the head end. This causes the ramped portion  483  to push against cylindrical member  487 . As a result, cylindrical member  487  is urged radially inwardly, such that it causes connection point  430  to recede radially inwardly into the body of the car seat and disengage from the recesses  137  in the base, the stroller or other apparatus. This allows the car seat to be removed from the stroller. The cylindrical member  487  is normally biased to the radially extended position (shown in  FIG. 26 ) by a biasing member, such as a spring (not shown). Thus, when the upper member  482  is released and returned to its rest position, the cylindrical member  487  moves back to the radially extended position. 
       FIG. 27  shows a bottom view of the car seat in the area of the connection point  430 . In addition to the connection point  430 , a claw  488  optionally extends downwardly from the bottom of the car seat.  FIG. 28  shows an expanded side view of this optional feature. When upper member  482  is in its natural rest position, connection point  430  extends radially from the body of the car seat. In addition, claw  488  extends outwardly from the bottom of the seat. This claw  488  engages with catch  120  (See  FIG. 3 ). When the upper member  482  is pulled toward the head end, it causes the claw  488  to recede into the shell, thereby releasing the claw from the catch  120  and allowing the car seat to be removed from the base. In one embodiment, the upper members  482  terminate in elongated slots  487 , through which the connection points  430  pass.  FIG. 29  shows another view of this optional feature. Note that upper member  482  also includes a looped portion  489  to support the claw  488 . 
       FIG. 30  shows the release handle  481  of the unlock mechanism  460 . The release handle  481  is located on the underside of the car seat. In one embodiment, a lip  490  is also located on the underside of the car seat and can be used as leverage to actuate the release handle  481 . In this embodiment, the user may position their palm against the lip  490 , with their fingers grasping the handle  481 . By moving their fingers toward the palm, the release handle  481  is moved upward (axially), thereby actuating the unlock mechanism  460 .  FIGS. 31-32  show additional views of the lip  490  and release handle  481 .  FIG. 32  also shows an elongated opening  491  in the plastic shell that provides a track for the release handle. The release handle  481  is able to move up and down within this opening  491  via radially extending protrusions. 
       FIG. 33  shows a view of the release handle  481  and its connection to upper members  482   a,b . In this embodiment, the upper members  482   a,b  terminate with an aperture  492  at the end nearest the release handle  481 . The radially extending protrusions of the release handle  481  pass through this aperture, thereby connecting the upper members to the release handle. In certain embodiments, shown in  FIG. 34 , the release handle  481  terminates in an oval shaped knob  493 , having a shape and size similar to the aperture  492  in the upper member  482 . To connect these pieces, the release handle  481  is held at a ninety-degree angle to its normal orientation, so that the knob  493  can pass through the apertures  492 . Then, upon proper orientating the release handle  481 , the knobs are rotated 90 degrees, preventing them from passing back through the apertures  492 . 
     In other configurations, the release handle  481  and upper members  482  may be a unitary part. In still other embodiments, other fastening mechanisms are used to hold the release handle  481  and upper members  482  together. 
       FIG. 35  shows a view of the car seat mounted to the base. In the embodiment shown, the two locations where the car seat attaches to the base are highlighted by circles  498  and  499 . Note that belt guide  105  passes between two attachment areas  498 ,  499 . This configuration gives the car seat and base added stability. Any sudden changes in speed of the vehicle in the forward or backward direction will necessary cause a force to be exerted on the infant child restraint system. By placing the belt guide  105  between the two attachment areas  498 ,  499 , the rotation of the base  100  and seat about the axis created by the belt guide  105  is significantly reduced. 
     In many prior art systems, the handle is smooth on three sides, with an exposed side, typically containing ribs for strength. Handles are traditionally made this way due to the complexity of molding a unitary part with four smooth surfaces. However, these conventional handles can be unsightly, when viewing this exposed side.  FIG. 36  shows the handle  440  used with the infant child restraint system. The handle  440  consists of three parts; a left handle  501 , a right handle  502 , and a handle cap  503 . As can be seen in better detail in the following figures, the left handle  501  and right handle  502  are concave in shape, and do not have any exposed sides. 
       FIG. 37  shows the outside view of right handle  502 . The lower portion of the handle ends at a cylindrical structure  504 , adapted to connect to the car seat. The outside edge  505  of the handle  502  has a generally concave shape. The handle  502  also has a curvilinear shape. 
       FIG. 38  shows a top view of right handle  502 . The concave shape of the outside edge  505  is visible, especially at the point where the handle meets the cylindrical structure  504 . The distal end of the right handle  502  includes a fastening hole  506 , and a handle attachment mechanism  507 , for attaching the right handle  502  to the left handle  501 . 
       FIG. 39  shows a view of the inner edge  508  of the right handle  502 . Note that the inner edge  508  also has a concave portion  509 . In this embodiment, the handle attachment mechanism  507  includes an oblong tab, which is adapted to mate with a similarly shaped opening in the left handle  501 . To join these parts, the oblong tab  507  is inserted through the oblong opening in the left handle  501 . In the preferred embodiment, the tab and opening are offset by about 90° from one another. This orientation allows the handles are rotated with respect to each other to lock them together. 
       FIG. 40  shows a top view of the right handle  502 . The fastening hole  506  and handle attachment mechanism  507  are shown. The concave shape of outside edge  505  is also visible. 
       FIG. 41  shows an expanded view of the handle attachment mechanism  510  of left handle  501 . As described above, in one embodiment, the tab  507  is oblong and mates to a corresponding oblong hole in the left handle  501 . Although an oblong, or oval shaped, tab and opening are shaped in the figures, other shapes are possible. Any non-symmetrical shape can be used. For example, a rectangular shaped tab and opening can also be employed, where the rectangular tab is preferably oriented 90° relative to the rectangular opening. This arrangement allows the two handles to lock together. 
       FIG. 42  shows a top view of the left handle  501  and right handle  502  joined together. The tab  507  is locked into the opening  509 , thereby holding the parts together. The area near the handle attachment mechanism is typically where the user would hold the handle. Therefore, a cap is placed over at least this portion of the handle assembly, to protect the user&#39;s hand from the sharp edges. Fastening holes  506  are used to secure the handle cap. 
       FIG. 43  shows a top view of the left handle  501 , right handle  502  and handle cap  515 . The holes  516  in the handle cap  515  align with the fastening holes  506  in the handles  501 ,  502 . Screws or other fastening devices can then be used to secure the handle cap  515  to the handles. 
     Although the handle assembly described above is made using two parts (i.e. a left handle  501  and a right handle  502 ) and a handle cap, this is only one possible embodiment. In another embodiment, the handle assembly is molded as a unitary piece, which attaches at two points to the shell  450 . In this embodiment, the handle cap  515  may optionally be attached to the unitary piece, to provide a more comfortable surface for the user to grasp. In other embodiments, the user grasps the unitary piece.