Patent Publication Number: US-2010127480-A1

Title: Foldable Stroller and Fold Linkage for Same

Description:
RELATED APPLICATION DATA 
     This patent is related to and claims priority benefit of U.S. provisional application Ser. No. 61/118,193 filed on Nov. 26, 2008 and entitled “Stroller and Fold Linkage for Same.” This patent is also a continuation-in-part of U.S. patent application Ser. No. 12/410,243 filed on Mar. 24, 2009 and entitled “Foldable Stroller and Fold Interlock Mechanism.” Each of the above noted related applications is incorporated in its entirety herein by reference. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure is generally directed to foldable strollers, and more particularly to a foldable stroller with a frame fold linkage that is hidden or housed within one or more stroller frame components. 
     2. Description of Related Art 
     Foldable strollers are known in the art. A typical foldable stroller has a frame assembly and a toddler or child seat supported by the frame assembly. Components of the frame assembly collapse or fold relative to one another when the structure is folded. A typical foldable stroller has fold links, or drive links, that are exposed in plain sight. On many strollers, one or more of the various exposed frame links and frame elements, as well as the geometry of same, drive folding of the stroller frame. For example, a user may fold the handle on a typical stroller, whereby the other frame components are driven to also fold upon movement of the handle. These drive or fold links and elements typically meet at fold joints, which can create shear and/or pinch points. These frame points can catch or pinch things small enough to fit between or within the components. Known fold joints and fold linkage arrangements also tend to detract from the overall appearance of the strollers. Fold joints can also fail from wear and tear. 
     The typical “solutions” to these problems do not actually solve the problems or address the disadvantages. Instead, the so-called solutions typically involve attempting to divert attention away from the drive or fold links and cumbersome fold joints using creative coloring, camouflaging, fancy exterior treatments, and/or integration of the visible fold linkage components into the aesthetic design of the rest of the stroller. Many strollers produced by Graco Children&#39;s Products Inc., for example, have tubes or stampings painted a different, and often darker, color in order to divert attention to other aspects of the stroller. 
     Other strollers simply cover these links and joints with fabric, such as from the stroller basket, in order to mask the fold linkage components from plain view. On some strollers, the drive links are integrated into the design of the stroller by making the components out of exotic materials, such as anodized aluminum, carbon fiber, textured plastics, or the like. On some strollers, the fold linkage or drive link components are designed in such a way that the links, although required only to drive the folding motion of the frame, look like they are structurally integral to the frame configuration. 
     SUMMARY 
     In one example according to the teachings of the present invention, a foldable stroller has a frame assembly that is reconfigurable between an in-use frame configuration and a folded frame configuration. The frame assembly can have a first frame part and a second frame part movable between respective in-use positions and folded positions relative to one another that correspond to the in-use and folded frame configurations. A fold joint can be connected to the first frame part and to the second frame part and can have a joint pivot about which the first and second frame parts pivot relative to one another between the respective in-use and folded positions. A fold link can have one end coupled to part of the frame fold joint at a pivot point spaced from the joint pivot and can have an opposite end coupled to the first frame part at a connection point spaced from the fold pivot. When the second frame part is pivoted from the in-use position toward the folded position, the fold link can drive movement of part of the frame assembly toward the folded frame configuration. The fold link can be hidden within an interior of the first frame part with the frame assembly in the in-use configuration. 
     In one example according to the teachings of the present invention, the frame assembly can have left and right sides. Each side can have one of the first and second frame parts, one of the fold joints, and one of the fold links. 
     In one example according to the teachings of the present invention, the first frame part can be a rear leg of the frame assembly. In one example according to the teachings of the present invention, the second frame part can be a push bar of a handle assembly. 
     In one example according to the teachings of the present invention, a stroller can have a shuttle slidable within the interior of the first frame part. The opposite end of the fold link can be connected to the shuttle. 
     In one example according to the teachings of the present invention, the fold joint can include a cam positioned within the interior of the first frame part with the frame assembly in the in-use configuration. The cam can be pivotable out of the interior when the frame assembly is moved toward the folded configuration. 
     In one example according to the teachings of the present invention, a cam can close an opening into the interior of the first frame part with the frame assembly in the folded configuration. 
     In one example according to the teachings of the present invention, the one end of the fold link can be connected to a cam of the fold joint. 
     In one example according to the teachings of the present invention, the frame assembly can include a third frame part coupled to the first frame part at a pivot. A stub portion of the third frame part can extend beyond the pivot and be connected to the opposite end of the fold link. 
     In one example according to the teachings of the present invention, the stroller can include a stand off connected to and extending forward from the first frame part. A pivot for a third frame part can be carried on a free end of stand off. 
     In one example according to the teachings of the present invention, a foldable stroller frame assembly is reconfigurable between an in-use frame configuration and a folded frame configuration. The frame assembly can have a fold joint defining a joint pivot, a first frame part connected to the fold joint, and a second frame part connected to the fold joint. The first and second frame parts can be pivotable relative to one another about the joint pivot between a respective in-use orientation in the in-use frame configuration and a folded orientation in the folded frame configuration. A fold link can have one end coupled to a pivot point spaced radially from the joint pivot and can have an opposite end coupled to the first frame part at a connection point spaced from the fold pivot. The fold link can fold part of the frame assembly toward the folded frame configuration as the second frame part is pivoted about the joint pivot toward the first frame part. The fold link can extend lengthwise along an interior portion of the first frame part when the frame assembly is in the in-use configuration. 
     In one example according to the teachings of the present invention, the first frame part can be a rear leg of the frame assembly and the second frame part can be a push bar of a handle assembly. 
     In one example according to the teachings of the present invention, an upper end of a rear leg can be connected to the fold joint and a lower end of a handle push bar can be connected to the fold joint. 
     In one example according to the teachings of the present invention, an upper end of the first frame part can be connected to the fold joint. A cam can be fixed to a portion of the fold joint connected to the second frame part and can move about the joint pivot in concert with movement of the second frame part. 
     In one example according to the teachings of the present invention, the one end of the fold link can be connected to a cam and the opposite end of the fold link can be connected to a shuttle slidably positioned within the interior of the first frame part. 
     In one example according to the teachings of the present invention, a stroller frame assembly can have a link slot extending lengthwise along and formed in the opposite end of the fold link, a shuttle positioned and slidable within the interior of the first frame part, and a pin movable with the shuttle and captured in the link slot. 
     In one example according to the teachings of the present invention, a stroller frame assembly can have a shuttle slot formed through a shuttle in the interior of the first frame part and oriented generally normal to the orientation of a link slot in the opposite end of the fold link. A pin can be connected to the fold link, movable with the shuttle, and captured within the shuttle slot. 
     In one example according to the teachings of the present invention, a stroller frame assembly can have a curved slot formed through and along the first frame part. A pin can be connected to the fold link and captured in the curved slot. 
     In one example according to the teachings of the present invention, a stroller frame assembly can have a third frame part pivotally connected to a pivot carried on a free end of a stand off that extends from the first frame part. A stub portion of the third frame part can extend beyond the pivot. A pin can be carried on the stub portion spaced from the pivot. 
     In one example according to the teachings of the present invention, a stroller fold joint assembly can have a first frame part and a second frame part pivotally connected to the first frame part at a joint pivot so as to be movable relative to one another about the joint pivot between an in-use orientation and a folded orientation. A fold link can have one end coupled to a pivot point spaced radially from the joint pivot and can have an opposite end coupled to the first frame part at a connection point spaced from the joint pivot. A third frame part can be pivotally connected relative to the first and second frame parts and connected to the one end of the fold link. The third frame part can be movable between an in-use orientation and a folded orientation relative to the first frame part. The fold link can move lengthwise within an interior of the first frame part when the first and second frame parts move between the in-use and folded orientations. The fold link can pivot the third frame part toward the folded orientation as the second frame part is pivoted about the joint pivot toward the folded orientation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Objects, features, and advantages of the present invention will become apparent upon reading the following description in conjunction with the drawing figures, in which: 
         FIG. 1  shows a perspective view of one example of a stroller constructed in accordance with the teachings of the present invention, the stroller being shown without soft goods and in an in-use configuration. 
         FIG. 2  shows the stroller in  FIG. 1  with the seat assembly exploded from the frame assembly of the stroller. 
         FIG. 3  shows a close-up, partial cut away, and inside perspective view of the left side fold joint on the stroller in  FIG. 2 . 
         FIG. 4  shows an exploded view of the fold joint in  FIG. 3  and part of the seat assembly in  FIG. 2 . 
         FIG. 5A  shows a perspective and fragmentary cross-section view taken along line V-V of the fold joint in  FIG. 2 . 
         FIG. 5B  shows a partial cross-section, fragmentary, and phantom view of the fold joint in  FIG. 5A . 
         FIG. 6  shows an outside perspective view of the fold joint in  FIG. 3  upon actuation of the fold actuator. 
         FIG. 7  shows the fold joint in  FIG. 5A  with the handle moved to a partially folded position. 
         FIG. 8  shows the fold joint in  FIGS. 5A and 7  with the handle moved to a completely folded position and the front and rear leg in a partially folded position. 
         FIG. 9  shows the fold joint in  FIGS. 5A ,  7 , and  8  with the front and rear leg in a completely folded position. 
         FIG. 10  shows the frame assembly of the stroller in  FIG. 2 , minus the seat assembly, in a completely folded configuration. 
         FIG. 11  shows a perspective view of another example of a stroller constructed in accordance with the teachings of the present invention, the stroller being shown minus the soft goods and in an in-use configuration. 
         FIG. 12  shows the stroller in  FIG. 11  with the seat assembly exploded from the frame assembly. 
         FIG. 13  shows a close-up, partial cut away, and outside perspective view of the left side fold joint of the stroller in  FIG. 12  and in a completely folded condition. 
         FIG. 14  shows an outside, partial cut away, partial phantom view of the fold joint in  FIG. 13 . 
         FIG. 15  shows a perspective view of the stroller in  FIG. 11  in a completely folded configuration. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The disclosed foldable stroller assemblies solve or improve upon one or more of the above-noted and/or other problems and disadvantages with prior known strollers. In one example, a foldable stroller is disclosed that has a fold joint with drive components hidden or housed at least partially within the frame structure of the stroller. In one example, the disclosed stroller has a fold joint with a substantially hidden linkage that drives folding of the stroller upon moving the handle from a normal use position to a folded position. In one example, the disclosed stroller has a fold joint with a substantially hidden linkage housed within a frame tube of the stroller frame structure. In one example, the disclosed stroller has fold joints with hidden drive links that drive folding of the stroller. 
     Turning now to the drawings,  FIG. 1  shows one example in perspective view of a foldable stroller  50  constructed in accordance with the teachings of the present invention. As described below, the stroller  50  is reconfigurable between an in-use or set-up configuration, as depicted in  FIG. 1 , and a folded or compact configuration. The disclosed stroller  50  has but one of many alternate frame assembly shapes and configurations that could be employed within the spirit and scope of the present invention. In the disclosed example, the stroller  50  has a frame assembly or chassis  51  supported by a pair of front wheels assemblies  52 , each having one or more front wheels  53 , and a pair of rear wheels  54 , each of which can be constructed in a conventional manner. In this example, the frame assembly or chassis  51  has a pair of opposed frame sides, each with a pivotable frame fold joint  56  interconnecting various components of the frame assembly. Each frame side in this example has a rear leg  58  laterally spaced from the rear leg of the other frame side and extending down and angled rearward from the corresponding fold joint  56  on the respective side. A lower end of each rear leg  58  is coupled in a conventional manner to one of the rear wheels  54 . 
     A foldable stroller is conceivable within the spirit and scope of the invention that has a different frame structure with no distinct pair of frame sides. It is also conceivable that the disclosed invention could be employed on a stroller with only one frame fold joint or more than two frame fold joints. As noted below, it is also conceivable that the disclosed invention could be employed utilizing an alternate child support structure on the frame assembly, other than a toddler or child seat assembly as described with respect to the examples herein. 
     In this example, the frame assembly  51  has a front leg assembly  60  that is constructed to form a pair of laterally spaced apart front legs  62 . Each front leg  62  extends forward and downward on its respective frame side. Each front leg  62  terminates at a forward end attached in a conventional manner to one of the front wheel assemblies  52 . The front leg assembly  60  also includes a transverse cross-bar  64  and a transverse cross-brace  66 . The cross-bar  64  interconnects the opposed rear ends of the two front legs  62 . The cross-brace  66  is located spaced from both the forward and rear ends of the front legs  62  and extends transversely between the front legs. Each of the front legs  62  is pivotally coupled at a leg pivot L to a stand-off  68  that projects forward from the respective rear leg  58 . A leg stub  70  is formed or created at the rearward end of each front leg  62  by a portion of each front leg extending beyond the pivot L. The distal or free end of the stub  70  on each frame side is pivotally connected to the respective rear leg  58  at a pivot S, which is slidable along a curved track or slot  72  on the inner facing side of the respective rear leg. 
     In the disclosed example, the frame assembly  51  also includes a handle assembly  80  extending upward and rearward from the fold joints  56 . The handle assembly  80  generally has a pair of laterally spaced apart push bars  82 , one coinciding with each frame side. Each push bar  82  has a lower end  83  joined to a respective one of the fold joints  56  as described below. The handle assembly  80  is a continuous U-shaped structure including the two push bars  82  and a curved top or end bar  84 , which extends transversely between and connects the upper ends of the push bars  82 . In the disclosed example, a stanchion assembly  86  extends upward and rearward from the end bar  84  of the handle assembly  80 . The stanchion assembly  86  has a pair of laterally spaced apart connector columns  88 , which project further rearward away from the end bar  84 . A latch actuator or fold actuator  90  is positioned between the columns  88  and spaced from the end bar  84 . A handle bar  92  or handle is coupled to the distal ends of the columns  88  and spaced from the end bar  84 . In this example, the actuator  90  is carried on an underside of the handle bar  92  between the stanchion columns  88 . 
     In general, the actuator  90  can be pulled by a user inward or upward into the handle bar  92 . This movement of the actuator  90  can pull on cables (discussed below) running from the actuator, through the stanchion assembly  86 , the end bar  84 , and push bars  82 , to the fold joints  56 . The cables release latches in the fold joints (also discussed below). Upon release of the latches, the stroller frame assembly  51  can be folded. The fold joints  56  and release of same is described in greater detail below. 
     In this example, the handle bar  92  is generally C-shaped with an arcuate or curved configuration. The curvature is arranged so that the handle bar  92  is concave toward the direction of the back end of the frame assembly  51 . Any part of the handle bar  92  may be grasped by the caregiver to push the stroller. The concave curvature of the handle bar  92  also allows the caregiver to step forward, closer to the stroller, and thus closer to the child seat occupant, during use of the stroller  50 . The shape, configuration, and construction of the handle bar  92  and the actuator  90  can vary and yet function satisfactorily for the purposes of the disclosed invention. For example, the handle bar  92  can be a linear element, be a multi-part structure, have an oval hoop shape, employ umbrella-type handles, or be an otherwise complexly curved structure. In addition, the actuator  90  can be placed on the end bar  84 , on or between the columns  88 , on a different part of the handle bar  92 , or the like. Further, the actuator  90  can require a rotary action, a linear pull or squeeze, can be a pivoting lever, or the like. Various forms of these types of actuators are known in the stroller art. 
     As shown in  FIGS. 1 and 2 , the stroller assembly  50  in this example has a removable child support structure  100  in the form of a toddler seat or seat assembly. The seat assembly  100  can be attached to and removed or detached from the frame assembly in this example. Thus, the child support structure is repositionable between two positions or states: 1) a usable state, as in  FIG. 1 , as a seat to support a child on the frame assembly  51  in the in-use configuration; and 2) an unusable state, as in  FIG. 2 , detached or removed from the frame assembly  51  and thus not usable as a seat on the frame assembly. The seat assembly  100  depicted herein is shown without soft goods. In use, the seat would have a seat structure defining a seat back and seat bottom as commonly known in the art for such a toddler-type seat. The seat assembly  100  is removable and can be reversible in this example. The seat assembly  100  can thus be installed on the frame assembly  51  in a forward facing or normal use orientation represented in  FIG. 1  or in a reverse or rear facing orientation where the seat occupant would face rearward toward the handle bar  92 . The seat is not shown herein in the reverse orientation, but for the purposes of the present invention would function essentially in the same manner. In this example, the seat assembly  100  is not a foldable structure and thus is to be removed prior to folding the frame assembly  51 . 
     The seat assembly  100  is best illustrated in  FIG. 2  and has an upper seat frame  102 , a lower seat frame  104 , and a pair of connecting structures  106  located on the opposed sides of the assembly. The connecting structures  106  connect the upper and lower frames  102 ,  104  to one another and also connect the seat assembly  100  to the stroller frame  51 . In general, the upper frame  102  would support and/or define a seat back part in conjunction with other components (not shown) of the seat assembly. Similarly, the lower seat  104  would support and/or define a seat bottom part in conjunction with other components (not shown) of the seat assembly. In this example, each of the seat frames is a U-shaped structure. The upper frame  102  generally follows the contour of, but is sized to nest within, the handle assembly  80 . The upper seat frame  102  has a pair of spaced apart frame legs  108  that terminate at lower ends, which connect to the respective connecting structures  106 . Similarly, the lower seat frame  104  has a pair of spaced apart frame legs  110  that terminate at upper ends, which also connect to the respective connecting structures  106 . 
     In the disclosed example, a cupholder assembly  112  is connected to and extends forward from a respective one of the connecting structures  106 . These cupholders  112  are optional and can be eliminated or can be replaced by some other structure such as an arm bar, a child tray, or the like. In addition, the upper seat frame  102  has a cross-member  114  extending between the frame legs  108 . The lower seat frame  104  has a similar cross-member  116  extending between the frame legs  110 . These cross-members  114 ,  116  can optionally support portions of a seat back and seat bottom, respectively, during use of the seat assembly and can provide rigidity and strength to the overall seat structure. The seat assembly  100  also has a pair of release buttons  118 . One of the release buttons  118  is positioned on the underside of each of the connecting structures  106  adjacent the corresponding frame legs  108 . The release buttons  118  are actuated to remove the seat assembly  100  from the frame assembly  51  as represented in  FIG. 2 . 
     The seat assembly  100 , including the upper and lower frames  102 ,  104 , the connecting structures  106 , and the release buttons  118 , can vary in configuration and construction within the spirit and scope of the present invention. The overall shape of the seat can also vary. The shape and configuration of the connecting structures  106 , as well as the location and function of the release buttons  118 , can also vary. In addition, the seat assembly  100  in this example, as well as the seat assembly in the subsequent example disclosed herein, can be replaced by other child support structures. For example, an infant car seat adapter for mounting a car seat, carrier, or carry cot can be attached to the frame assembly  51  in place of the seat assembly  100 . Alternatively, a direct mount car seat, carrier, carry cot, or other child support structure can be attached to the frame assembly in the same or a similar manner as the seat assembly  100  described herein. 
       FIG. 3  shows a close-up view of the left side fold joint  56  of the frame assembly  51  with the seat assembly  100  removed. The right side fold joint  56  is essentially identical and thus will not be described in detail herein. The description of the left side fold joint provided below is equally applicable to the right side joint.  FIG. 4  shows an exploded view of the left side fold joint  56  and the connecting structure  106  of the seat assembly  100  and depicts the major components for each.  FIGS. 5A and 5B  show cut-away sections of the assembled fold joint  56 . Each of these figures shows the components in the set-up configuration of the stroller as in  FIGS. 1 and 2 . The terms inward, inner, inside, and the like are used herein to refer to the side of a component positioned, arranged, oriented, or facing the middle of the stroller (i.e., toward the other side of the stroller frame). The terms outer, outward, outside, and the like are used herein to refer to the side of a component positioned, arranged, oriented, or facing the exterior of the stroller frame or away from the stroller. 
     With reference to  FIGS. 3-5B , the fold joint  56  generally has a joint housing  130  with a lower or leg connector  132  configured to mate with and connect to the rear leg  58 . The lower connector  132  forms a fixed joint to the rear leg and maintains a static orientation between the rear leg and the joint housing  130  in this example. The connection can vary but in one example the rear leg  58  and the leg connector  132  can be telescopically joined and then fastened to one another. The joint housing  130  also has a housing section  134  from which the lower connector  132  extends. The housing section  134  is generally hollow on its interior and defines a lengthwise slot or receptacle  136  along its length. The joint housing  130  also defines a main pivot axis P or joint pivot that extends transversely through the housing. A rear end of the slot or receptacle  136  enters a space  138  between opposed sides of the joint housing  130  centered on the pivot axis P. 
     A puck  140  is attached via a handle or upper connector  141  to the lower end of the push bar  82 . A hatchet shaped cam  142  extends from an edge of the puck  140  opposite the connector  141 . A top surface  144  of the cam  142  is essentially flat, as are the opposed side faces of both the cam and the puck  140 . An extension  146  of the cam  142  extends downward and has a link space or slot  149  into the end of the cam in the extension. A curved end surface  148  on the cam has a generally constant radius relative to the pivot axis P in this example. A latch-receiving bore  150  is formed into the end face  148  and extends through the cam  142 , the puck  140 , and the connector  141 , and lengthwise into the push bar  82 . The bore  150  is generally aligned with the axis of the push bar  82 . 
     A pair of bearing plates  151  and  152  is spaced apart from one another, extends from the joint housing  130 , and defines the space  138  therebetween. The outer bearing plate  152  of the pair creates a circular outer bearing surface that surrounds the pivot axis P on the outer side of the housing. The outer bearing surface (not shown) bears against an outer face  153  on the puck  142  when the joint  56  is assembled. A similar inner bearing surface  154  is defined on the inner bearing plate  151  of the pair on the housing  130 . The inner bearing surface  154  also surrounds the pivot axis P on the inner side of the housing  130  and bears against an inner face (not shown) on the opposite side of the puck  142  in the assembled joint. An outer cover plate  156  can be secured over the exterior surface of the joint housing  130 . The cover plate  156  can be for decorative purposes and/or can cover fasteners used to assemble the joint housing  130  and the fold joint  56 . 
     A shell section  158  is carried on an inner side of the joint housing  130  and adjacent the inner bearing surface  154 . A shell cover  160  is secured to the shell section  158  and creates a cavity within a shell when assembled. The shell cover  160  defines the inner boundary of the fold joint  56  in this example. The shell section  158  and shell cover  160  contain therein an optional interlock or lock pin  162  in the cavity when assembled. The lock pin  162  has a locking end  164  on the outward side and has a contact end  166  on the inward side of the pin. A fixed or integral washer  168  is positioned on a shaft of the pin  162  and differentiates the two ends of the locking pin. A pin spring  169  is received over the locking end  164  and bears against the washer  168  when assembled. The other end of the pin spring  169  bears against an inside surface of the shell section  158  and biases the lock pin in an inward direction toward and protruding through the shell cover  160 . 
     A latch finger  170  is aligned with and received in the latch bore  150  of the cam  142 . A puck bore  172  is located at the center of the puck  140  and is aligned with the pivot axis P when the joint is assembled. Likewise, a plate bore  173  is formed through each of the bearing plates on the housing and is also aligned with the axis P. The puck  140  seats in the space  138  between the surfaces  152 ,  154  of the housing plates with the puck bore  172  aligned with the plate bores  173  on the axis P. A main pivot pin  176  is received through the puck bore  172  and the cam bearing plate bores  173 . The fold joint main pivot axis P is defined by the pin  176 . As depicted in  FIG. 4 , the underside of the latch finger  170  has a travel limiter in the form of an elongate notch  177  formed up into the finger. The main pivot pin  176  is captured in the notch  177  as shown in  FIG. 5A . 
     A pull cable  174  with a slug (not shown) on one end is routed from the earlier described actuator  90 , through the handle assembly  80  along the push bar  82 , and into the joint housing  130 . The cable  174  is seated in a cable slot  178  extending lengthwise along the latch finger  170 . The slug seats within a slug receiver  180  positioned at the end of the cable slot  178  to secure the cable to the latch finger  170 . A latch spring  182  is positioned at a cable end  183  on the latch finger  170 . One end of the spring  182  bears against the latch finger  170  and the other end bears against a fixed surface within the latch bore  150 . The spring  182  biases the latch finger  170  in a direction away or outward from the lower end  83  of the push bar  82  and toward the end of the cam  142 . The latch finger  170  has an interlock hole  184  formed through the finger in this example. A cap  186  covers the open end of the slot  136  in the joint housing  130  opposite the puck  140 . 
     The free end  187  of the latch finger  170  is flat on a top surface  185  and curved or angled on an end surface  188 . With the frame assembly  51  in the set-up configuration, the free end  187  of the latch finger  170  protrudes into the slot  136  of the joint housing  130 . The flat top surface  185  at the free end  187  bears against a surface SS within the slot  136  as shown in  FIG. 5A . The latch finger  170  is prevented from pivoting upward without first withdrawing the latch finger to clear the free end  187  from the slot  136  in the housing  130 , as described below. This arrangement retains the push bar in the setup orientation. 
     The connecting structure  106  of the seat assembly  100  generally has a frame connector  190  with a center hub  192 , an upper connector  194  extending radially from the hub, and a lower connector  196  extending radially from the hub in a direction generally opposite the upper connector. The upper connector  194  is configured to connect with a free end of the seat frame leg  108 . As with the rear leg  58  to housing connector  132  joint described above, the upper connector  194  can vary in construction, but in one example can have a portion telescopically received in an open end of the seat frame leg  108 . Fasteners can be used to secure the two components together. Similarly, the lower connector  196  is configured to connect and fasten to a free end of the seat frame leg  110 , but can also vary from the example shown. 
     In this example, the release button  118  is received in a slot (not shown) under the upper connector  194 . The seat assembly  100  has a seat mount  210 , which in this example is positioned on the center hub  192 . The seat mount  210  has an outer side with an inverted, U-shaped, female coupling  214  that surrounds on three sides a generally flat face  216  of the mount. The coupling  214  is open at the bottom of the seat mount. A chamfer or ramp  218  is disposed at an open bottom edge of the flat face  216 . A seat or male connector  222  projects from the exterior, but inner facing, side of the shell cover  160 . In this example, the seat connector  222  defines a mounting point for attaching the seat assembly  100  or other child support structure to the frame assembly  51 . The male connector  222  has a complementary U shape to engage and seat within the coupling  214  of the seat mount  210 . The male connector  222  has a rounded top  224  and linear sides  226  permitting the seat mount  210  to be lowered onto the connector. The button  118  can actuate or release a seat lock or latch (not shown herein) that secures the seat coupling  214  to the connector  222  on the shell cover  160 . The seat assembly can be latched to the seat connectors  222  when installed and be released therefrom by actuating the buttons  118 . 
     The cupholder  112  is connected in this example to the seat mount  210 , but can be eliminated or attached to another component such as one of the frame connectors  194 ,  196 . The cupholder  112 , or a portion thereof, can be integrally formed as a part of one of these components or can be separately attached. 
     As depicted in  FIG. 3 , the latch finger  170  cannot be released and the frame assembly  51  in this example cannot be folded while the seat assembly  100  is installed on the stroller  50 . The lock pin  162  and the face  216  on the seat mount  210  each act as part of an interlock mechanism in this example. The lock pin  162  and face  216  cooperate with one another to prevent actuation of the fold latch by locking the latch finger  170  in the latched position. With the frame assembly  51  in the set-up configuration and the seat assembly  100  mounted to the fold joint  56 , the flat face  216  on the seat mount  210  bears against the contact end  166  of the pin  162 . The pin is forced outward against the bias force of the pin spring  169 . In this locked state or position, the locking end  164  of the pin  162  is aligned with and seats through the hole  184  in the latch finger  170 . With the seat assembly  100  mounted to the stroller, the latch finger  170  cannot move. Even if the user were to attempt to actuate the actuator  90 , which would pull on the cable  174  and the latch finger  170 , the locking end  164  of the pin  162  would prevent movement of the latch finger. 
     In order to fold the frame assembly  51 , a user must first remove the seat assembly  100  from the stroller  50 . To do so, a user pulls upward on the release button  118  to disengage the seat or female coupling  214  from the male connector  222 . Once unlatched or released, the seat mount  210  can be lifted from the seat connector  222  on the shell cover  160 . When the flat face  216  of the seat mounts  210  clears the contact end  166  of the respective lock pin  162 , the pin spring  169  will fire the lock pin  162  inward through the shell cover  160 . The locking end  164  of the pin  162  then withdraws from the hole  184  in the latch finger  170 . This unlocked state or position is shown in  FIG. 3 . With reference to  FIG. 3 , the tip  236  on the contact ends  166  of the lock pin  162  is rounded for purposes to be discussed shortly hereafter. 
     With the pin  162  free of the hole  184  in the latch finger  170 , the user is then free to manipulate the actuator  90 , which in turn pulls on the cable  174 . As shown in  FIG. 6 , the cable withdraws the latch finger  170  toward or into the lower end  83  of the push bar  82  against the force of the latch spring  182 . As described above, the free end  187  of the latch finger  170  clears the housing body and the surface SS within the slot  136  allowing the fold joint  56  to pivot or fold. To fold the stroller frame assembly  51 , the user pushes the handle assembly  80  downward toward the rear legs  58 . The handle assembly  80 , and particularly the push bars  82 , pivots about the main pivot axis P on the fold joints  56 . The travel limiter notch  177  can be sized to stop travel of the latch finger  170  in each direction, i.e., the latched direction and the released or unlatched direction, by the pivot pin  176  hitting either end of the notch. The notch  177  can also be sized to align the locking hole  184  with the locking pin  162  in the latched position. 
     In accordance with the teachings of the present invention, and with reference to the left side fold joint  56  shown in  FIGS. 4 ,  5 A,  5 B, and  7 - 9 , the frame assembly  51  of the stroller  50  can be reconfigurable between an in-use frame configuration ( FIGS. 1 and 2 ) and a folded frame configuration ( FIG. 10 ). The frame assembly can employ a first frame part and a second frame part that are movable between respective in-use positions and folded positions relative to one another that correspond to the in-use and folded frame configurations. In the disclosed example, the first frame part can be a rear leg  58  and the second frame part can be a push bar  82  of the handle assembly. The fold joint  56  can be connected to the first frame part and to the second frame part, such as is described above. The fold joint  56  can have a joint pivot, such as the main pivot P, about which the first and second frame parts pivot relative to one another between the respective in-use and folded positions. As described below, a fold link can have one end coupled to part of the frame fold joint at a pivot point that is spaced from the joint pivot and can have an opposite end coupled to the first frame part at a connection point spaced from the fold pivot. When the second frame part is pivoted from the in-use position toward the folded position, the fold link can drive movement of part of the frame assembly toward the folded frame configuration. In one example, the driven part can be a third frame part, such as the front leg  62 . 
     The fold link as disclosed herein can be hidden within an interior of the first frame part with the frame assembly in the in-use configuration. The frame assembly can have left and right sides, as described above. Each of the frame sides can have one of the first and second frame parts, one of the fold joints, one of the fold links, and one of the driven frame parts. The fold link can have one end coupled to a pivot point spaced radially from the joint pivot and can have an opposite end coupled to the first frame part at a connection point spaced from the fold pivot or joint pivot. The fold link can fold the first frame part and/or another frame part toward the folded orientation as the second frame part is pivoted about the joint pivot. The fold link can extend lengthwise along an interior portion of the first frame part when the frame assembly is in the in-use configuration. A third frame part of the stroller can be pivotally connected relative to the first and second frame parts and connected to the one end of the fold link. The third frame part can be movable between an in-use orientation and a folded orientation relative to the first frame part. The fold link can move lengthwise within the interior of the first frame part when the first and second frame parts move between the in-use and folded orientations. The fold link can pivot the third frame part toward the folded orientation as the second frame part is pivoted about the joint pivot toward the folded orientation. 
     In one example, a fold link  250  is housed within the rear leg  58 . The fold link has a lower end  251  pivotally connected to a slidable shuttle  252  that is also housed within and slidable lengthwise along the interior of the hollow rear leg. The lower end  251  of the link  250  is slidably and pivotally connected to the shuttle  252 . In this example, the link&#39;s lower end  251  has an elongate link slot  253  formed lengthwise along the link and relative to the leg  58 . The shuttle  252  also has an elongate slot  254  through the shuttle body. The shuttle slot  254  is oriented normal or perpendicular to a lengthwise axis of the rear leg  58  and, thus, generally normal to the link slot  253 . 
     A spacer link  238  is mounted to the front leg stub  70  between the front leg  62  and the rear leg  58 . The spacer link  238  has one end  239  fixed to the leg stub  70 . Both the spacer link  238  and stub  70  are pivotally connected at the leg pivot L to the stand off  68  by a pivot pin  243 . The opposite end  240  of the spacer link  238  is fixed to the leg stub  70  at the pivot S near the end of the stub. The spacer link  238  is thus fixed to the stub  70  and moves in concert with the stub about the leg pivot L. A boss  241  protrudes laterally outward from the end  240  of the spacer link  238  and projects into the rear leg  58  through the curved slot  72  in the side of the leg. A shuttle pin  242  extends through the shuttle slot  254 , the link slot  253 , the curved slot  72  in the leg  58 , and the boss  241 . The pin  242  links these components together, but can slide within or along the shuttle slot  254 , the link slot  253 , and the curved slot  72 , as described below. In the in-use configuration and latched condition, the shuttle pin  242  seats at the uppermost end of the link slot  253 , the lowermost end of the curved slot  72 , and the forward end of the shuttle slot  254 . 
     The other, upper end  255  of the link  250  is pivotally coupled to the cam  142  at a pivot K defined by a pin  256  received through an aperture  257  in the cam extension  148 . The pivot K is located just below the latch bore  150  and is spaced radially from the handle pivot or main pivot axis P. The puck  140  and the cam  142  in this example are seated between the spaced apart inner and outer plates  151 ,  152 . The link  250  is movably positioned in the space  138  between the two plates and further within the slot  149  in the cam extension  148 . As the user pushes down on the handle assembly  80 , the cam  142  pivots upward about the axis P from within the hollow end of the rear leg  58 . Movement of the handle assembly  80  moves the cam  142 , which in turn moves the link  250  and thus the shuttle  252 , as described below. 
     With reference to  FIGS. 6 and 7 , with the latch finger  170  unlatched, the handle assembly  80  is free to rotate downward about the pivot axis P from the unfolded or in-use position toward the rear leg  58 . The cam  142  and pin  256  pull the fold link  250  upward within the hollow interior of the rear leg  58  as the handle assembly  80  rotates. The handle assembly  80  will travel downward and the link  250  will move up a predetermined distance until the bottom end of the link slot  253  hits the shuttle pin  242 . As the handle assembly  80  is rotated further downward toward the rear leg  58 , the link  250  will pull the pin  242  upward, which drives upward movement of the shuttle  252  within the rear leg  58 . Since the shuttle pin  242  is connected to the leg stub  70  at the pivot S, the leg stub will begin to rotate about the leg pivot L with the boss  241  of the spacer link  238  sliding upward along the curved slot  72 . 
     As the leg stub  70  moves, the front leg  62  rotates about the leg pivot L downward and inward toward the rear leg  58  as shown in  FIG. 8 . The curved slot  72  extends lengthwise along the leg  58 , but curves end-to-end so that the slot does not lie along the leg axis. In this example, the shuttle pin  242  is free to translate within the shuttle slot  254 , and thus can travel along and follow the curved slot  72 . Both the link  250  and the stub end  70  of the front leg also follow the path of the track or slot  72 . Also in this example, the handle assembly  80  and the push bar  82  are in a stowed or fully folded position when adjacent and generally parallel to the rear leg  58 . However, in this example, the front leg  62  has not yet fully folded rearward toward the rear leg  58  when the handle assembly is fully folded downward. Further, the shuttle pin  242  is only about half way up the curved slot  72  and is still bottomed out at the lower end of the link slot  253 . This component arrangement retains the front and rear legs  62 ,  58  and, thus, the front and rear wheels  53 ,  54  spaced apart from one another during folding. The frame assembly  51  thus can remain relatively stable resting on the wheels  53 ,  54  as the handle assembly  80  is folded. 
     With reference to  FIGS. 8 and 9 , the front and rear legs  62 ,  58 , respectively, can rotate further toward one another after the handle assembly  80  is fully folded. The shuttle pin  242  can move further upward within the curved slot  72  and within the link slot  253  until reaching the completely folded configuration. The legs  58 ,  62  can abut one another, the pin  242  can bottom within the curved slot  72 , and/or the pin can contact the top end of the link slot  253  when the frame assembly  51  is completely folded. If a user lifts the stroller frame assembly  51  upward, gravity can force the front and rear legs  62 ,  58  together from the position in  FIG. 8  to the position in  FIG. 9 . Alternatively, a user can manually push the legs  58 ,  62  together to completely fold the frame assembly  51 . As a result of pushing down on the handle assembly  80 , and then either lifting the frame assembly  51  or pushing the legs together, the front leg  62  pivots downward and rearward toward the rear leg  58  and the handle assembly  80  pivots downward toward the rear legs to the compact, completely folded configuration in  FIG. 10 . 
     The primary fold components, and in particular the hidden link  250 , the shuttle  242 , and the cam  142 , are completely hidden from view in the in-use configuration and are internally contained within the stroller structure. The front leg stub  70  is the only visible fold joint component and is relatively short, discretely hidden adjacent and by the rear leg  58 , and thus not readily apparent as part of the fold mechanism. The disclosed fold joint  56  and fold component arrangement significantly reduce the existence of shear or pinch points while folding or unfolding the frame assembly  51 . The primary fold joint parts are contained within the housing  130 , within the rear leg  58 , and/or between surfaces of the cam  142  at all times. Only the leg stub  70  and the slot  72  are exposed at all times. The cam  142  is exposed during folding and in the folded configuration. However, the exposed cam surfaces are flat and do not expose or create any pinch points. The slot  72  can be backed entirely, such as in this example, by a surface of the shuttle as it slides within the leg  58  to further minimize any pinch points at the stub  70  to leg  58  connection. The cam  142  can be shaped and sized to seat fully within, and thus be completely hidden within the hollow end of the rear leg  58  with the frame assembly  51  in the in-use configuration. The cam  142  in this example can also be sized and shaped to block the exposed end of the hollow rear leg  58  with the frame assembly  51  in the folded configuration to further minimize and pinch or shear points. In this example, the joint housing  130  covers the top open end of the rear leg  58 . The slot  136  and space  138  remain open to allow travel of the link  250  upward and outward during folding. The cam  142  closes off the opening into the rear leg  58  created by the slot and space in the housing  130  during use in this example. 
     With the frame assembly in the folded configuration of  FIG. 10 , the seat assembly  100  cannot be reinstalled in this example. The interlock mechanism is retained in the unlocked state, preventing attachment of the seat mount  210 . The contact end  166  of the lock pin  162  blocks attachment of the seat mount  210  to the seat connector  222 . The locking end  164  of the lock pin  162  is borne against a side bearing face of the cam  142  and is blocked from outward movement. The frame  51  must first be unfolded to the set-up configuration in  FIG. 2  and the latch must then be latched. In this example, the frame assembly can include a storage latch. As shown in FIGS.  1  and  10 , a conventional storage latch can be employed to retain the frame assembly  51  in the folded configuration. For example, the storage latch can include a plastic, flexible latch or catch arm  258  mounted to one of the rear legs  58  and a catch pin  259  projecting from the corresponding front leg  62 . The catch arm  258  can engage the catch pin  259  when the frame assembly is folded, either manually or automatically, and can be manually released in order to unfold the frame assembly, as is known in the art. 
     When the stroller frame  51  is unfolded and the handle assembly  80  is raised to near the in-use position, the latch finger  170  is in the latched position protruding from the bore  150  in the cam  142 . However, the curved end surface  188  of the latch finger  170  will bear against an edge  260  near the surface SS in the slot  136  of the housing body at the end of the space  138 . This surface to surface engagement temporarily forces the latch finger  170  against the bias of the latch spring  182  and back into the bore  150 . Once the slot  136  aligns with the bore  150  and, thus, the finger  170 , the latch finger will fire by force of the latch spring  182  back into the slot  136  under the surface SS of the housing  130  and again retain the frame assembly  51  in the in-use configuration. 
     Once in this unfolded and latched configuration, the hole  184  and the pin  162  are again aligned with one another as in  FIGS. 3 and 5B . The pin  162  is still retained in the unlocked position, however, by force of the pin spring  169 . The seat mount  210  can be lowered onto the male connector  222 . The rounded tip  236  of the lock pin  162  will bear against and ride along the chamfer  218  and then onto the face  216  as the seat mount  210  is lowered. The chamfer  218  and face  216  will drive the locking pin  162  against the biasing force of the spring  169  back into the shell cover  160 , which in turn drives the pin into the hole  184  of the latch finger  170 . The seat assembly  100  and the interlock mechanism will again prevent the fold joints  56  from being unlatched. The frame assembly  51  cannot be folded until the seat is removed, as discussed above. 
     In the above example, the interlock mechanism incorporates the chamfer  218  and face  216  of the seat mount  210 , the locking pin  162 , the pin spring  169 , a bearing face of the cam  142 , and the hole  184  in the latch finger  170 . Once the seat assembly is removed and thus in an unusable state, the interlock mechanism fires to the unlocked state or position. This in turn unlocks the latch finger so that the fold joint  56  can be folded. The seat assembly  100  cannot be installed on the frame assembly while the frame assembly is unfolded. The pin  162  position of interlock mechanism prevents such seat reattachment. The interlock mechanism thus adds a degree of safety to the stroller  50  be requiring the seat assembly to be removed in this example before folding the frame assembly  51  and by not allowing the seat assembly to be re-attached until the frame assembly is unfolded and locked. Thus, a child cannot remain seated in the seat while the stroller  50  is folded. The interlock mechanism is an optional feature that need not be utilized in conjunction with the hidden fold linkage aspect of the invention. Alternately, the interlock mechanism can vary from the example shown and described herein, as will become evident to those of ordinary skill in the art upon reading this disclosure. 
     The hidden fold link arrangement can also vary in configuration and construction from the example disclosed and described above, as can the configuration of the stroller  50  and frame assembly  51 .  FIGS. 11 and 12  show another example of a foldable stroller  300  constructed in accordance with the teachings of the present invention and in an in-use or set-up configuration. In this example, the stroller  300  has a frame assembly  301  that is substantially the same as the frame assembly  51  described above with respect to the stroller  50 . Thus, when describing aspects of the stroller  300 , the same reference names and reference numbers are utilized. New reference numbers are used only to introduce elements that are different from the earlier example. The stroller  300  in this example has a removable seat assembly  100  as the child support structure, also shown minus the soft goods. Only an optional canopy support bar  302  from the first example has been removed in this example.  FIG. 12  shows the seat assembly  100  removed from the frame assembly  301 . 
     In this example, the front leg assembly  60  has an alternate configured top cross-bar  304 . This change shows just one small example of how the stroller frame assemblies  51 ,  301  can be altered without departing from the spirit and scope of the present invention. Also, the spacer link  238  between the leg stub  70  and the slot  72  in the rear leg  58  has been eliminated. This change shows just one other small example as to how the hidden fold linkage components can be altered within the spirit and scope of the present invention. 
       FIGS. 13 and 14  show an outside, partly cut away and partial phantom view of the left side fold joint  56  on the stroller frame assembly  301  in  FIG. 12 . Other than the elimination of the spacer link  238 , only the fold link  250  from the prior example is different in this example. An alternate fold link  306  is pivotally connected at its upper end to the cam  142  and at its lower end to the shuttle pin  242 . In this example, the lower end  308  of the link  306  has only an aperture for connection to the pin. The link  306  has no elongate link slot  253  as in the prior example. This, there will be no motion lag between the handle assembly and the front leg  62  during folding in this example. As soon as the handle assembly  80  begins to move downward during folding, the hidden link  306  will move upward and the shuttle pin  242  and shuttle  252  will move upward. This in turn will immediately start to fold the front leg  62  toward the rear leg  58 . In this example, when the handle assembly  80  reaches the fully folded position depicted in  FIGS. 13-15 , the front leg  62  will also be fully folded. 
       FIG. 15  shows the frame assembly  301  completely folded. The frame assembly  301  functions essentially the same as the assembly  51 , other than as described herein. To unfold the assembly, a user need only pivot the handle assembly  80  toward the in-use position. This will directly and immediately begin to unfold the front leg assembly  60  relative to the rear legs  58  in this example. Without the slot  253 , as on the link  250 , use of the link  306  produces no motion lag between the handle assembly  80  and front legs  62 , both during folding and unfolding. In the prior assembly  51 , when the stroller is folded, there is a motion lag as the shuttle pin  242  travels along the link slot  253  before the link  250  moves the slot. When the stroller is unfolded, as long as the leg  62  and leg  58  are completely folded, there would be no motion lag because the pin  242  is seated at the top of the link slot and would immediately be pushed downward. However, if the legs were only partly folded as in  FIG. 8 , the handle would move partly upward without moving the front leg  62  while the pin traveled from the bottom of the link slot to the top. 
     In each disclosed embodiment, the links  250  and  306  are bent or curved to fit within the leg  58 , to prevent binding during folding and unfolding, and to be able to translate lengthwise and laterally therein as the upper and lower pivot points K and S move. The link configuration and construction can vary from the examples shown within the spirit and scope of the invention. In this example, the links  250  and  306  fit within a lengthwise slot extending along the middle of the body of the shuttle  252 . In alternate embodiments, the links can be attached to either side of the shuttle body or to a top or bottom thereof as well. 
     As will become evident to those having ordinary skill in the art, the disclosed fold joints and fold linkages can vary in configuration and construction and yet fall within the spirit and scope of the present invention. In general, the intent of the fold joints and linkages disclosed and described herein is to create a more aesthetically pleasing stroller structure, while reducing or eliminating pinch and shear points during folding or unfolding of the stroller. The disclosed optional interlock mechanism prevents a stroller seat from being unsafely utilized when the stroller is being folded or after the stroller is completely folded. The various components of these devices can be altered and rearranged and yet fall within the spirit and scope of the present invention. The materials utilized to fabricate the various components can also vary. The invention is not intended to be limited to any specific type of material for any of the components. 
     Although certain foldable strollers and fold mechanisms and joints have been described herein in accordance with the teachings of the present disclosure, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the disclosure that fairly fall within the scope of permissible equivalents.