Abstract:
A car seat for transporting a child in an automobile is described which is convertible from a rear-facing infant carrier into a forward-facing toddler carrier by the inclusion or removal of a separable headrest. The car seat features a belt adjustment system as well as a crotch belt adjustment system in addition to front and rear restraint attachment components.

Description:
TECHNICAL FIELD 
     This invention relates generally to a juvenile convertible car seat with a restraining harness and moveable headrest. More specifically, the invention includes adjustability of an internal harness to fit various sized and growing children in such a manner that the harness never requires disassembly and corresponding reassembly in a new position, thereby reducing the potential to misuse the product, as well as the ability to use the product over a wider age span through the ability to selectively include or remove a headrest depending on the size of the occupant. 
     BACKGROUND OF THE INVENTION 
     Juvenile convertible car seats are designed for use with growing children. These car seats are designed to convert the car seat from a rear facing and reclined position for infants (from birth up to 20, 22 or even 30 lbs.) to an upright and forward facing position for toddlers (up to 40 or even 65 lbs. or more). Convertible car seats are secured on an automobile seat with the automobile seat belt(s) threaded through specific forward or rear facing belt paths, relative to a forward or rear facing installation. Construction of a convertible car seat typically comprises of a molded plastic seat shell that is essentially a bucket seat shell with a seat and back support surface, forward extending side supports, a molded-in frame, and other details for the attachment of pads, belt systems, and other components. The belt system, or internal harness, restrains the child occupant and is generally a 5-point system with a crotch strap, two lap belts, and two shoulder belts. The belt system also includes some sort of adjuster to loosen or tighten the belts, and it is typically located at or under the front of the seat for easy access. A sewn fabric seat pad provides comfort. 
     The child population is increasing in weight and size relative to age and safety advocate groups are urging parents to keep children in child restraints (especially those with an internal harness) as long as possible. Therefore, convertible car seats are typically large and are getting larger to contain older and heavier children. 
     When used rear facing for an infant, the convertible car seat must be reclined to properly support the developing child. This creates a challenge, especially for a large convertible seat. Juvenile car seats are typically used in the back seat of an automobile and the seat back of the reclined and rear facing juvenile car seat often interferes with the seat back of the front automobile seat. This incompatibility prevents the juvenile car seat from properly reclining or even prevents its use entirely. 
     Harness system adjustment, specifically that of the two shoulder belts, has always been an area of misunderstanding and misuse by the consumer. Typically, juvenile car seat backs have multiple sets of slots at different heights to correspond to a growing child&#39;s shoulders. To adjust the shoulder belts from one slot to another, the consumer has to un-secure the harness and unthread the shoulder belts from the current slots and rethread them through the desired slots and then re-secure. Crotch straps on some car seats have multiple use positions also and some must be unthreaded, moved and rethreaded similar to shoulder belts. This disassembly and reassembly introduces risks to the use of the car seat as the correct and crucial reassembly relies entirely on the consumer, who may not be mechanically inclined. 
     Some juvenile convertible car seats have a means to slide the shoulder belts up or down to a new height without disassembly and rethreading. This is accomplished with a sliding carriage behind and/or in front of the seat back that the shoulder belts pass over or through. The shoulder belts pass through the seat back of the molded shell via a single pair of large, vertically elongated slots that correspond to the range of motion of the adjustable carriage. The carriage position is adjusted by a mechanism that is located behind the seat back and often hidden from the user and is thus non-obvious and/or difficult to use. Even fewer convertible car seats have the ability to adjust the crotch strap without disassembly, and current adjustment means are, again, non-obvious and difficult. 
     LATCH stands for Lower Anchorages and Tethers for Children and is an industry standard of child restraint attachment. It typically includes a length of belt with a clip at each end and an adjuster in between to adjust the length of the belt. The belt can be threaded through either the rear facing or forward facing belt paths of the convertible car seat and the clips attach to metal loops on either side of the seating area behind the seat cushion of the auto seat. The metal loops are attached to the frame of the car. With the clips attached to the loops, the LATCH belt can be adjusted tightly and the car seat is secured. The use of LATCH is optional but car seats are required to be so equipped as an alternate method of attachment to the standard auto seat belts. 
     Side impact performance is a growing concern with juvenile car seats, and while high sides on a seat, along with the internal harness do contain the child occupant, the juvenile car seat itself can still slide side-to-side even when properly installed. This movement is caused by the juvenile car seat sliding laterally relative to the auto belts or LATCH belt. A solution is integral belt clamps that reside within or adjacent to the rear and/or forward facing belt paths of the juvenile car seat. These clamps hold the auto or LATCH belts tight to the juvenile car seat and prevent or minimize side-to-side sliding relative to these belts. 
     Most convertible car seats have a recline feature that manages the seat recline position for comfort and/or proper positioning in forward or rear facing installations. Rear facing installation always requires more recline to properly support a developing infant. 
     It has become common for nearly all children&#39;s car seats to include at least one cup or drink holder. These take many forms and are either removable or retractable by some means. 
     The purpose of this invention is to solve these problems with current car seats in a practical, reliable, convenient, and cost effective manner. It will make transportation of a growing child safer and more convenient. 
     SUMMARY OF THE INVENTION 
     This invention is a juvenile convertible car seat which can be used rear facing for infants and forward facing for toddlers, in an automobile. The focus of this invention is on a reasonable fit of a large convertible car seat in an automobile (specifically rear facing) and adjustability of an internal harness to fit various sized and growing children in such a manner that the harness never requires disassembly and corresponding reassembly in a new position, which introduces potential misuse. 
     This convertible car seat includes a seating surface, a seat back surface, raised sides, and structural frame rails on either side behind the seat and back surfaces running nearly the length of the entire seat. The basic structure is molded in one plastic part. The sides and backrest are lined with energy absorbing foam. It also includes a 5-point internal harness as described above which is adjustable to fit various sizes of children without disassembling and rethreading the harness. The car seat also includes a recline stand, auto belt clamps, forward and rear facing belt paths, and a removable upper back section. 
     The removable upper back section, when removed, reduces the seat back height and minimizes interference with the front automobile seats when the car seat is installed rear-facing in a rear automobile seat. This allows a proper recline angle for an infant. The remaining non-removable back area is sufficiently large to support an infant and maintain seat structure. The removable back section of this invention incorporates portions of the forward extending sides of the car seat. 
     Attachment of the removable upper back section can be achieved any number of ways but in this case it is accomplished with a generally “U” shaped metal component that is fastened to the removable upper back with the legs of the “U” pointing downward. The legs of the “U” slide into the structural frame rails behind the seat back surface of the molded plastic seat shell. At least one slot is formed in at least one of the downward pointing “U” legs and is engaged by at least one spring biased tooth that resides in the corresponding structural frame rail(s) of the shell. Engagement of the tooth to the slot on the “U” leg is automatic once the legs are inserted far enough into the rails. Removal of the upper back is accomplished by applying pressure to a tooth removal lever to overcome the spring bias, disengaging the slot on the “U” leg, and sliding the upper back and its legs out of the frame rails. The removable upper back must be installed on the juvenile seat once the child is about 20 or 22 pounds to provide the additional support height necessary for the larger child. 
     Another advantage of the removable back is that the seat can be packaged with the removable back disassembled. This allows for a smaller box which saves warehousing and shipping costs—especially important when shipping from overseas. 
     The two shoulder belts of the 5-point harness system of this invention are adjusted vertically by means of a movable carriage or transverse beam located behind the seat back. The shoulder belts pass through this carriage and through two large vertical slots in the seat back, that correspond generally to the vertical range of motion of the carriage. The carriage slides generally vertically or parallel to the molded seat back between the two main structural rails located behind the seat back. 
     This carriage comprises of two parts that trap a pair of inwardly spring-biased plungers that extend laterally from either side of the carriage. These plungers penetrate vertical slots molded through each of the two structural frame rails. These slots allow a range of motion of the carriage and the penetrating plungers and include apertures that correspond to teeth on the plungers. The apertures and corresponding plunger teeth define the various height positions of the carriage, and ultimately, the shoulder belts passing through the carriage. The teeth are urged into the apertures via the spring bias. Each plunger includes a finger grip area that the user may utilize to pull the plunger outward, overcoming the spring and disengaging the tooth from the particular aperture. Both plungers must be pulled outward simultaneously to disengage the teeth on both structural frame rails and then moved, along with the carriage, to a desired height and new set of apertures. Releasing the plungers allows the springs to urge the teeth inward into the new set of apertures, latching the carriage into the new position. Because the vertical slots and apertures are located on the outside of the structural frame rails, the user can make the desired shoulder belt height adjustment without uninstalling the car seat and can visually confirm what position the carriage is in and that the teeth on the plungers are fully engaged. 
     The two vertical shoulder belt slots in the seat back surface are unique from the equivalent slots of other car seats in that their shape is such that no cover plate is required in the occupant area. Each of the two vertical slots is actually a series of generally horizontal belt slots located at corresponding positions to where the shoulder belts pass through the carriage as positioned by the latching apertures on the main shell rails. The number of the horizontal belt slots is the same number of latching apertures. The series of slots is connected by a narrow central slot of approximately 1″ in width and the edges are angled at approximately 45° to transition smoothly into the horizontal belt slots. All corners are rounded such that the connecting slots assume a wave-like shape on each side. The wave-like sides of the connecting slots allow the shoulder belts to slide easily from position to position (by means of the carriage) eliminating or greatly reducing the chance that the belt will “hang” as the position is changed. The central connecting slot is narrow to preserve as much of the back seating surface as possible and therefore eliminating the need for any kind of cover plate in front of the slots. 
     The crotch strap is also adjustable away from or closer to the back surface without any disassembly. This is accomplished with a large hole molded in the seat surface of the shell with a series of teeth under the seating surface on either side of the hole. A sliding cover plate on the inside of the seat covers the large hole. A crotch strap receiver part with a raised center section with a slot to receive the crotch strap is slideably attached to the bottom of the cover plate up through the hole in the shell such that the raised center section penetrates a smaller hole in the cover plate. The cover plate and crotch strap receiver are biased toward each other via two springs secured to the cover plate. The crotch strap receiver has teeth that correspond and engage teeth on the shell via the spring bias. To adjust, the user grips the bottom of the crotch strap on the raised center section of the crotch strap receiver, pushes down to disengage the teeth and slides the crotch strap, crotch strap receiver, and cover plate to the desired position. The spring bias urges the teeth of the crotch strap receiver and the shell to engage at whatever position the crotch strap receiver is moved. The top cover plate simply slides along the seating surface and provides cover for the large hole. The large hole in the shell defines the overall range of motion of the crotch strap receiver and ultimately, the crotch strap. 
     The recline of this convertible car seat is achieved by means of a pivoting U-shaped arm with a horizontal beam and two legs terminating in hubs located under the shell. The arm pivots via a lug on each hub of the arm that penetrates a corresponding hole molded on the outside of each structural shell rail. The recline arm pivots rearward or forward to either recline or make the seat upright. The arm is retained in either reclined or upright position via an outwardly spring biased plunger located at the end of each hub. The shell in this area is shaped such that the outwardly biased plungers create an interference with the shell, holding the recline arm in place in either position. The spring bias is only strong enough to hold the recline arm in place and is easy to overcome by the user who only has to rotate the arm out of one position, which compresses the springs and moves the plungers out of the way, and allows the arm to swing to the next position where the biased plungers again retain arm position. 
     The forward facing auto and LATCH belt path is located about a third of the way up the seat back surface and is situated in front of the two main structural rails of the seat. It is defined by a trough and an opening at either end to allow threading of the auto or LATCH belts. This trough is open to the front. To further strengthen the belt path, a filler component is attached to the front of the trough and closes it, making a double-walled structural box. The filler also covers structural shell ribs as well as smoothing and further defining the belt path. A belt clamp at the center of the belt path filler compresses on the auto or LATCH belts and prevents unwanted side to side motion of the car seat relative to the auto seat and belts. This clamp consists of two parts, a lock arm and a cam that interacts with the filler component. The lock arm is pivotally attached to the belt path filler part just below where the auto belt(s) lie. The cam component is pivotally attached to the opposite end of the lock arm. With the auto or LATCH belts in place, the user pivots the lock arm down over the belt(s) and rotates the cam down which engages two lugs on the cam part with two ledges molded onto the filler part. The interaction of the cam lugs with the ledges keeps the lock arm closed, and maintains pressure on the auto or LATCH belts. 
     The rear facing auto and LATCH belt path is located at the front of the convertible car seat, just forward of the crotch strap attachment and on the seating surface. It is defined by openings in the vertical walls on either side of the seating surface that direct the auto or LATCH belts laterally over the seating surface and through each opening. Adjacent to each of these openings is a recess. Inside each recess is a belt clamp assembly that encompasses the width of the recess which closes the opening and strengthens the path in this area. Pivotally attached at the front of the clamp assembly base is a lock arm. Pivotally attached to the rear of the clamp assembly base is a cam. The pivot axis of this cam is perpendicular to that of the lock arm axis. The auto or LATCH belts are threaded through the belt path, and over the clamp assembly base. To clamp the auto or LATCH belts, the user pivots the lock arm component down over the belts and rotates the cam part over the end of the lock arm opposite its attachment to the clamp base. The cam interaction with the lock arm relative to the clamp base keeps the lock arm closed and maintains pressure on the auto or LATCH belts. The other end of the belt path, on the opposite side of the seat is a mirror image of this clamp base/lock arm/cam assembly. Both forward facing and rear facing belt clamps minimize unwanted side to side motion of the juvenile car seat relative to the auto seat when clamped onto the auto or LATCH belts. 
     The LATCH belt assembly can be stored inside the convertible car seat when not in use inside two wells located to the rear and at either side of the seating surface. A small tether belt attaches the LATCH belt assembly permanently to the interior of the car seat shell. This tether is long enough to allow the LATCH belt assembly to reach both the rear facing and forward facing belt paths, where it can be used to secure the convertible car seat. 
     These and other objects of the present invention will become more readily apparent from a reading of the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals indicate similar parts, and with further reference to the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may take physical form in certain parts and arrangements of parts, a preferred embodiment of which will be described in detail in the specification and illustrated in the accompanying drawings which form a part hereof, and wherein: 
         FIG. 1  is a front perspective of the convertible car seat in upright, forward facing configuration with upper back attached; 
         FIG. 2  is a rear perspective of the convertible car seat in upright, forward facing configuration with upper back attached; 
         FIG. 3  is a top view of the convertible car seat in upright, forward facing configuration; 
         FIG. 4  is a bottom view of the convertible car seat in upright, forward facing configuration; 
         FIG. 5  is a left side view of the convertible car seat installed in upright, forward facing configuration on an automobile seat; 
         FIG. 6  is a left side view of the convertible car seat in reclined, rear facing configuration on an automobile seat, with upper back removed; 
         FIG. 7  is a close up view of  FIG. 5  showing a cut-away section of the metal legs of the removable back inserted into the shell rail; 
         FIG. 8A  is a close up of  FIG. 7  showing detail of removable upper back retention spring and tooth engaging metal leg of the upper back; 
         FIG. 8B  is the same view as  FIG. 8A  but with metal leg of removable upper back partially disengaged from the tooth; 
         FIG. 8C  is the same view as  FIG. 8A  but with metal leg of removable upper back disengaged and showing no contact with the tooth; 
         FIG. 9  is a close up view of  FIG. 2  with the rear cover removed to expose moveable shoulder belt carriage with carriage cover also removed to expose spring-biased plunger mechanism at rest; 
         FIG. 10A  is a cut-away section through the spring-biased plunger mechanism of the shoulder belt carriage showing penetration and engagement of the left plunger into the left shell rail; 
         FIG. 10B  is a cut-away section through the spring-biased plunger mechanism of the shoulder belt carriage showing disengagement of the left plunger from the left shell rail with spring compressed; 
         FIG. 11A  is a cut-away section through the crotch belt receiver teeth and corresponding shell teeth showing engagement in the rearmost position; 
         FIG. 11B  is a cut-away section through the crotch belt receiver teeth and corresponding shell teeth showing disengagement and a phantom of an alternate position; 
         FIG. 12A  is a cut-away section through the crotch belt showing retention within the crotch belt receiver that is spring biased up towards the cover plate; 
         FIG. 12B  is a cut-away section through the crotch belt showing the crotch belt receiver depressed, with springs compressed, and receiver teeth disengaged from shell teeth; 
         FIG. 13A  is a close-up view of  FIG. 5  showing the recline leg in upright, forward facing position with plunger and corresponding spring exposed; 
         FIG. 13B  is a close-up left side view with recline leg in between reclined and upright position with plunger and corresponding compressed spring exposed; 
         FIG. 14A  is a cut-away view showing the forward facing belt path and belt clamp in the open position; 
         FIG. 14B  is a cut-away view showing the forward facing belt path and belt clamp in the closed position with cam unlocked; 
         FIG. 14C  is a cut-away view showing the forward facing belt path and belt clamp in the closed position with cam locked; 
         FIG. 15A  is a cut-away view showing the left rear facing belt clamp in open position with cam unlocked; 
         FIG. 15B  is a cut-away view showing the left rear facing belt clamp in closed position with cam unlocked; 
         FIG. 16A  is a cut-away section view through and normal to the left rear facing belt clamp showing it closed with the cam in unlocked position; and 
         FIG. 16B  is a cut-away section view through and normal to the left rear facing belt clamp showing it closed with the cam in locked position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings wherein the showings are for purposes of illustrating the preferred embodiment of the invention only and not for purposes of limiting the same. The figures show a convertible car seat with a detachable upper back to allow a proper rear facing installation in an auto as well as for the benefit of a smaller package size and with an adjustable shoulder harness mechanism that never requires rethreading of the harness and which can be adjusted from the front of the car seat when installed on an automobile seat, as well as other inventions. 
     As illustrated in  FIG. 1 , convertible car seat  10  has two major components, seat shell assembly  12  and removable upper back assembly  14 . Seat shell assembly  12  incorporates a seating surface  16 , a back surface  18  which are generally perpendicular to one another, and adjacent raised right side  20 R and raised left side  20 L. Raised sides  20 R and  20 L incorporate inner surfaces  26 R and  26 L respectively, and outer surfaces  30 R and  30 L respectively Inner surfaces  26 R and  26 L form the main inside contours of respective energy absorbing foam components  35 R and  35 L that span the entire inner side surfaces of seat shell assembly  12 . Back surface  18  defines the main outer contour of energy absorbing foam component  36  that covers the upper interior back surface of seat assembly  12 . 
     Removable upper back assembly  14  incorporates a back surface  22  and adjacent raised right side  24 R and raised left side  24 L. Raised sides  24 R and  24 L incorporate inner surfaces  28 R and  28 L respectively, and outer surfaces  32 R and  32 L respectively. Inner surfaces  28 R and  28 L and back surface  22  form the inner contour of energy absorbing foam liner  40  which spans the entire interior of upper back assembly  14 . 
     Removable upper back surface  22  is essentially an extension of seat shell assembly back surface  18 . Removable back inner surfaces  28 R and  28 L of raised sides  24 R and  24 L are essentially extensions of seat shell assembly  12  inner surfaces  26 R and  26 L of raised sides  20 R and  20 L. 
     Internal harness  42  includes shoulder/lap belts  44 R and  44 L, crotch belt  46  and buckle/latch assembly  48 . Harness adjuster  50  is located in front and directly below seating surface  16  where it is easily accessed. Tightening internal harness  42  is achieved by pulling adjuster belt  52  through the adjuster  50 , which is connected to and pulls on the shoulder/lap belts  44 R and  44 L better illustrated in  FIG. 2 . Loosening the harness is done by lifting a lever on the adjuster  50  and pulling on the shoulder belts which pulls adjuster belt  52  back into the adjuster  50 . 
     A sewn pad covers the majority of the car seat, but it is not shown for clarity. 
     Removable upper back outer surfaces  32 R and  32 L are essentially extensions of seat shell assembly outer surfaces  30 R and  30 L, respectively, as shown in  FIG. 2  Upper back outer surfaces  32 R and  32 L are joined together by the central rear surface  54 . These three surfaces define the essential shape of the plastic upper back component  38  of the upper back assembly  14 . Both rear surface  54  of the plastic upper back  38  and back surface  22  of the removable upper back  14  foam liner  40  are penetrated by hand grip  56 . 
     Seat shell assembly  12  outer surfaces  30 R and  30 L are intersected by main rails  58 R and  58 L located behind back surface  18  and below seating surface  16 . Main rails  58 R and  58 L share rear contoured surface  60 , bottom contoured surface  62  (also shown in  FIG. 4 ), and also include inner surfaces  66 R and  66 L and outer surfaces  64 R and  64 L, respectively. Inner surfaces  66 R and  66 L extend upward under the seat and are bridged by seating surface  16 . This combination of surfaces defines the essential form of the main molded plastic seat shell  34 . 
     Rear rail cover  68  connects main rails  58 R and  58 L and shares rear surface  60  with them. Rear cover  68  includes instruction storage recess  70 . Apertures  72  are located near the top of main rails  58 R and  58 L and accept angled metal component  74  of removable upper back assembly  14 .  FIG. 7  illustrates metal component  74  inserted through aperture  72  and down inside main rail  58 R/ 58 L.  FIG. 8A  more clearly shows spring  80  biasing tooth  82  into slot or notch  78  on metal component  74 . When metal component  74  is inserted into main rails  58 R and  58 L (better illustrated in  FIG. 8C ), angled tip  76  acts on tooth  82 , moving it out of the way and overcoming the bias of spring  80  (see  FIG. 8B ) to allow metal component  74  to pass far enough for alignment and consequential biased engagement of tooth  82  with slot  78 . Tooth removal lever  84  may be pulled to disengage tooth  82  from slot  78 , compressing spring  80 , for removal of metal component  74  from main rails  58 R and  58 L, also shown in  FIGS. 8B and 8C . 
     Movable shoulder belt carriage assembly  88  (synonymously moveable transverse adjustment beam) shown in  FIG. 9 , manages the height of shoulder belts  44 R and  44 L. Shoulder belts  44 R and  44 L pass through slots  100 R and  100 L in moveable carriage body  90  that lies between main rails  58 R and  58 L. Plungers  92 R and  92 L extend laterally from either end of carriage body  90  and penetrate substantially vertical slots  86 R and  86 L in main rails  58 R and  58 L. Springs  96  bias plungers  92 R and  92 L inward relative to carriage body  90  and drive tooth  94  located on each plunger  92 R and  92 L ( FIG. 10A ,  10 B) into recesses  98  located adjacent to vertical slots  86 R and  86 L in main rails  58 R and  58 L. A series of generally evenly spaced recesses  98  adjacent to vertical slots  86 R and  86 L (see  FIGS. 5-6 ) define the alternative vertical positions of carriage assembly  88 , and ultimately the vertical positions of shoulder belts  44 R and  44 L within the global range of adjustability permitted by vertical slots  86 R and  86 L.  FIG. 5  illustrates the highest position  110  while  FIG. 6  illustrates the lowest position  112 . Adjusting the height of the shoulder belt carriage assembly  88  requires that both plungers  92 R and  92 L be pulled outward simultaneously, overcoming biasing springs  96  and disengaging tooth  94  located on each plunger  92 R and  92 L from current position recesses  98  as shown in  FIG. 10B . The shoulder belt carriage assembly  88  can then be raised or lowered to the desired position where tooth  94  from each plunger  92 R and  92 L can align and engage with another position of recess  98  via the bias of spring  96  as shown in  FIG. 10A . 
       FIG. 1  shows right and left shoulder belt slots  102 R and  102 L. Each generally vertical slot  102 R and  102 L includes multiple generally horizontal shoulder belt slots  104 , a narrow and generally vertical connecting slot  106 , and transition ramps  108  forming an hourglass arrangement. The number and vertical position of horizontal slots  104  corresponds directly to the number and vertical position of recesses  98  adjacent to vertical slots  86 R and  86 L in main rails  58 R and  58 L. Narrow connecting slot  106  allows shoulder belts  44 R and  44 L to slide from one set of horizontal shoulder belt slots  104  to the next set of slots  104 , by means of movable shoulder belt carriage assembly  88 , without requiring that vertical slots  102 R and  102 L be as wide as horizontal slots  104  along their entire length. The narrow areas of connecting slot  106  between the horizontal slot  104  positions preserve and maximize back surface  18  to increase occupant support and comfort and eliminate the need for any type of cover plate to conceal what would be larger voids. Transition ramps  108  allow the shoulder belts to slide easily through the narrow connecting slot  106 , as shoulder belt height is adjusted from position to position, and reduces the chances of the shoulder belts “hanging up”. 
     Crotch belt  46  is adjustable away from or closer to back surface  18  of seat shell assembly  12  and best illustrated in  FIGS. 11A and 11B , and  FIGS. 12A and 12B . Crotch belt  46  is attached to belt receiver  114  through crotch slot  116 . Belt receiver  114  attaches below seating surface  16  and extends up through large opening  124  (also shown in  FIG. 4 ) in seating surface  16  of seat shell assembly  12  and through smaller opening  122  in cover plate  120  (also shown in  FIG. 3 ). Belt receiver  114  is coupled to and biased by springs  128 , upward, toward cover plate  120 , essentially sandwiching this area of seat shell  34 . Belt receiver  114  incorporates teeth  118  on each side that are sized and spaced to correspond with teeth  126  located underneath seating surface  16  that flank either side of large opening  124 . The bias of springs  128  on belt receiver  114  up toward cover plate  120  also biases crotch belt receiver teeth  118  up and into seat shell teeth  126 . This biased engagement maintains position of belt receiver  114  and ultimately, crotch belt  46 . Adjustment of crotch strap  46  position is accomplished by gripping the base of strap  46  where it enters belt receiver  114  at crotch slot  116 , and pushing down on receiver  114  to overcome the bias of springs  128  with cover plate  120  and disengaging the teeth  118  of receiver  114  from seat shell teeth  126  ( FIGS. 11B ,  12 B). With teeth disengaged, the belt receiver  118  and crotch belt  46  can be moved to a new position where teeth  118  of receiver  114  can align with and engage different shell teeth  126  by means of springs  128  as illustrated in  FIG. 11B . 
     Recline leg  130  manages the forward facing position  132  ( FIG. 5 ) and rear facing position  134  ( FIG. 6 ) of convertible car seat  10 . Recline leg  130  is rotatably attached to main rails  58 R and  58 L at pivot axis  140 . Adjacent to the attachment and pivot axis  140  of recline leg  130  is a recess defined by contoured surface  142  in both main rails  58 R and  58 L. Surface  142  is formed such that it limits the range of motion for recline leg  130  and defines upright position  132  where recline leg  130  supports the rear of convertible car seat  10  as illustrated in  FIG. 5  and reclined position  134  where recline leg  130  supports the front of convertible car seat  10  as illustrated in  FIG. 6 . Each side of recline leg  130  contains a sliding plunger  136  that is biased by springs  138  beyond the envelope of recline leg  130 . The bias of springs  138  forces plungers  136  to interfere with contoured surface  142 , maintaining recline leg  130  in either upright position  132  (also shown in  FIG. 13A ) or reclined position  134 , and preventing it from flopping freely between the two positions. The bias of springs  138  is only enough to support the weight of recline leg  130  itself, and is easily overcome by a consumer grasping and rotating recline leg  130  to change position.  FIG. 13B  illustrates recline leg  130  in between positions  132  and  134  with plunger  136  forced inside recline leg  130 , with spring  138  compressed and sliding along surface  142  until recline leg  130  is rotated to either position  132  or  134 . 
       FIG. 5  illustrates automobile seat  180  and the interaction with convertible car seat  10  in forward facing position  132 .  FIG. 6  illustrates automobile seat  180  and the interaction with convertible car seat  10  in rear facing position  134  and front automobile seat back  182  in close proximity to the top convertible car seat  10 . If removable upper back assembly  14  were installed on car seat  10 , it would likely interfere with front automobile seat back  182  and prevent car seat  10  from installing properly on automobile seat  180  in rear facing position  134 . 
     Forward facing belt path  184  incorporates an auto belt clamp  186  at its approximate center as shown in  FIG. 1 .  FIG. 14A  shows a side view of belt path  184  and belt clamp  186  with auto belt  156  threaded through belt path  184 . Lock arm  144  is pivotally attached to the lower part of belt path  184  at axis  152  and is shown in an open position. Cam  146  is pivotally attached to lock arm  144  at axis  154  and includes locking lugs  148 . Belt path  184  also includes locking ledges  150 .  FIG. 14B  shows lock arm  144  closed against auto belt  156  with cam  146  in an unsecured position.  FIG. 14C  shows cam  146  closed against lock arm  144  with locking lugs  148  of cam  146  engaged under locking ledges  150  of belt path  140 . Engagement of locking lugs  148  and ledges  150  prevent lock arm  144  from opening and maintains constant pressure on auto belt  156 . To release lock arm  144 , the user must rotate cam  146  upward, disengaging locking lugs  148  from locking ledges  150  so lock arm  144  can be rotated open, releasing pressure on auto belt  156 , which can then be unthreaded from belt path  184 . 
     Openings  160 R and  160 L as shown in  FIG. 3 , establish a rear facing auto belt path for convertible car seat  10  with rear facing belt clamps  162 R and  162 L adjacent to openings  160 R and  160 L and generally flush with seating surface  16 .  FIG. 15A  shows a side view of belt clamp  162 L, that comprises a clamp base  164 , lock arm  166  pivotally connected to the forward end of clamp base  164  at axis  168 , cam  172  pivotally connected to the rear edge of clamp base  164 , at axis  174  which is perpendicular to axis  168 , and auto belt  178 . Lock arm  166  is open and away from clamp base  164  and incorporates collar  170  on the end opposite axis  168 .  FIG. 15B  shows lock arm  166  closed and against clamp base  164  and auto belt  178 .  FIG. 16A  shows cam  172  in the unlocked position (as in  FIG. 15B ), with sleeve  176  of cam  172  in unsecured relationship to collar  170  on lock arm  166 . Rotating cam  172  down as shown in  FIG. 16B  moves sleeve  176  over collar  170  of lock arm  166 , securing lock arm  166  and maintaining constant pressure on auto belt  178 . 
     In the foregoing description, certain terms have been used for brevity, clearness and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover, the description and illustration of the invention is by way of example, and the scope of the invention is not limited to the exact details shown or described. This invention has been described in detail with reference to specific embodiments thereof, including the respective best modes for carrying out each embodiment. It shall be understood that these illustrations are by way of example and not by way of limitation.