Abstract:
The foldable baby stroller frame comprises a collapsible wheeled frame, a foldable upper frame, and at least a release mechanism. The collapsible wheeled frame comprises at least a front strut, a pair of rear struts and a lockable swivel base. The lockable swivel base is pivotally connected with the front strut and the rear strut, including a spring-loaded abutting slider for fixing the front strut and the rear strut in a using position. Preferably, a spring-loaded positioning member is installed for releasably engaging between the foldable upper frame and the lockable swivel base to fix the direction of the foldable upper frame. The release mechanism is manipulated by rotating a pair of push arms, when the push arms is rotated upwardly to a upright position, the spring-loaded positioning member is disengaged to permit the foldable upper frame changing its direction, and when the push arms is rotated downwardly, the spring-loaded abutting slider is retracted to permit the front strut and the rear strut rotating relative to each other.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 11/851632 filed on Sep. 7, 2007, entitled “FOLDABLE BABY STROLLER FRAME”, the disclosure of which is incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to a foldable stroller frame. More specifically, this invention relates to a stroller that has a collapsible wheeled frame having a lockable swivel base for pivotally supporting a foldable upper frame, and a release mechanism mounted on the foldable upper frame for actuating the folding of the collapsible wheeled frame and the foldable upper frame. 
       DESCRIPTION OF THE RELATED ART 
       [0003]    Traditional collapsible stroller frame normally has a pair of articulated joints disposed on opposite sides of the frame for pivotally connecting the push arms and the front struts thereof. 
         [0004]    As shown in  FIG. 12 , the articulated joint  9  used to connect the push arm  91  and the front strut  93 , typically includes an upper joint member  92  and a lower joint member  94 . The push arm  91  is connected the upper joint member  92  and has a distal portion pivotally connected to the lower joint member  94 . 
         [0005]    The lower joint member  94  is connected with the front strut  93  and has a slot  941  formed at the upper side thereof A connecting member  911 , latch member  912  and a spring  910  are movably mounted inside the lower end of the push arm  91 . When the push arm  91  is rotated about the lower joint member  94  to aligned to the front strut  93 , the spring  910  is functioning to bias the latch member  912  to engage with the slot  941 , so as to lock the articulated joint  9  in a non-rotatable state thereby to keep the push arm  91  and the front strut  93  in an erected position. 
         [0006]    When folding the collapsible stroller frame, the user may pull the latch member  912  backwardly through the connecting member  91  against the biasing of the spring  910  to unlock the articulated joint  9 , this made the push arm  91  is then rotatable, therefore, the traditional collapsible stroller frame is foldable for saving space of storage and transportation. 
         [0007]    As the lower joint member  94  of the articulated joint  9  is made of plastic material, in case the slot  941  is broken, the stroll may accidentally become folded in use, this shall endanger the baby passenger sitting inside. 
       SUMMARY OF THE INVENTION 
       [0008]    In order to avoid the possible danger of the traditional collapsible stroller frame, the present invention provides a foldable baby stroller frame with a different folding mechanism. 
         [0009]    The foldable baby stroller frame according to the present invention comprises a collapsible wheeled frame, a foldable upper frame, and at least a release mechanism. 
         [0010]    The collapsible wheeled frame comprises at least a front strut, a pair of rear struts and a lockable swivel base. 
         [0011]    The lockable swivel base is pivotally connected with the front strut and the rear strut, including a spring-loaded abutting slider for fixing the front strut and the rear strut in a using position. 
         [0012]    Preferably, a spring-loaded positioning member is installed for releasably engaging between the foldable upper frame and the lockable swivel base to fix the direction of the foldable upper frame. 
         [0013]    The release mechanism is manipulated by rotating a pair of push arms, when the push arms is rotated upwardly to a upright position, the spring-loaded positioning member is disengaged to permit the foldable upper frame changing its direction, and when the push arms is rotated downwardly, the spring-loaded abutting slider is retracted to permit the front strut and the rear strut rotating relative to each other. 
         [0014]    Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein: 
           [0016]      FIG. 1  is a perspective view of a preferred embodiment of the collapsible baby stroller frame of the present invention. 
           [0017]      FIG. 2  is a side view of the collapsible baby stroller frame of  FIG. 1 . 
           [0018]      FIG. 3  is a partially exploded perspective view of the collapsible baby stroller frame according to the preferred embodiment. 
           [0019]      FIG. 4  is a partially exploded perspective view of a foldable upper frame according to the preferred embodiment. 
           [0020]      FIG. 5  is a partially cross-sectional view of joint of the foldable upper frame according to the preferred embodiment. 
           [0021]      FIG. 6  is a partially schematic cross-sectional view showing the connecting of the collapsible wheeled frame and the foldable upper frame according to the preferred embodiment. 
           [0022]      FIG. 7  is a schematic cross-sectional view showing the locking mechanism of the pair of lockable articulated arms according to the preferred embodiment. 
           [0023]      FIG. 8  is an exploded perspective view of the pair of lockable articulated arms of the collapsible baby stroller frame according to the preferred embodiment. 
           [0024]      FIG. 9  is a side view illustrating the folding operation of the collapsible baby stroller frame according to the preferred embodiment. 
           [0025]      FIG. 10  is a side view illustrating the collapsible baby stroller frame in a folded position after the folding operation. 
           [0026]      FIG. 11  is a schematic side view showing the operation of the collapsible baby stroller frame according to the preferred embodiment. 
           [0027]      FIG. 12  is schematic cross-sectional view showing an articulated joint of traditional collapsible stroller frame. 
           [0028]      FIG. 13  is a side view illustrating an alternative embodiment of the collapsible baby stroller frame equipped with lockable swivel base. 
           [0029]      FIG. 14  is a partial cross-sectional view illustrating the assembly of the lockable swivel base and the collapsible wheeled frame. 
           [0030]      FIG. 15  is a partial cross-sectional view schematically illustrating the operation of the folding of the collapsible wheeled frame. 
           [0031]      FIG. 16  is an exploded view of the swivel rack and the release mechanism. 
           [0032]      FIG. 17  is a partial cross-sectional view illustrating an alternative embodiment of the assembly of the lockable swivel base and the swivel rack. 
           [0033]      FIG. 18  is a side view schematically illustrating the operation for changing the direction of the swivel rack. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0034]    Reference will now be made in detail to presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. An effort has been made to use the same reference numbers throughout the drawings to refer to the same or like parts. 
         [0035]    Referring to  FIGS. 1 and 3 , a preferred embodiment of the collapsible baby stroller frame according to the present invention comprises a collapsible wheeled frame  1 , a foldable upper frame  10 , and at least a release mechanism  5 . 
         [0036]    The collapsible wheeled frame  1  comprises at least a front strut  11  with castor wheels  13 , a pair of rear struts  12  with rear wheels  14 , a pair of lockable articulated arms  2 , and a swivel base  3 . 
         [0037]    The swivel base  3  is pivotally connected with the front strut  11  and the rear struts  12 , and further has a vertical shaft hole  31  for pivotally connecting and supporting the foldable upper frame  10 . 
         [0038]    The pair of lockable articulated arms  2  is pivotally connected between the front strut  11  and the rear struts  12 , and has a locked position for keeping the collapsible wheeled frame  1  in an un-foldable state and a foldable position for folding the collapsible wheeled frame  1 . 
         [0039]    The release mechanism  5  is operatively mounted on the foldable upper frame  10  and associates with the pair of lockable articulated arms  2  via a connecting member  56  for actuating the folding of the collapsible wheeled frame  1  and the foldable upper frame  10 . 
         [0040]    The foldable upper frame  10  includes a swivel rack  4 , a push arm  110 , and a pair of joints  100 . The pair of joints  100  are lockable and pivotable connect between the swivel rack  4  and the push arm  110 . 
         [0041]    Preferably, the collapsible wheeled frame  1  may further comprise a biasing member  20  which can be embodied as a pneumatic rod or resilient member for biasing and helping the folding the pair of lockable articulated arms. The biasing member  20  has one end pivoted to the rear strut  12 , and another end pivot to the middle portion of the pair of lockable articulated arms  2 . 
         [0042]    Referring to  FIGS. 3 and 5 , the swivel rack  4  includes a U-shaped arm  40 , a vertical shaft  401 , and a pair of mounts  41 . The pair of mounts  41  are mounted on the distal ends of the U-shaped arm  40  and have a connecting member  411  for detachably connecting and supporting a seat frame member  200  or a baby carrier (not shown). For instance, the connecting member  411  may be a plug extending upwardly from each of the mounts  41 , and the seat frame member  200  or a baby carrier may include a pair of sockets  201  for detachable engaging with the connecting member  411 . 
         [0043]    The vertical shaft  401  of the swivel rack  4  is connected on the middle portion of the U-shaped arm  40  and extended downwardly for pivotally mounted on the vertical shaft hole  31 . This allows caregivers to change the direction of the seat frame member  200  or the baby carrier by turning the swivel rack  4 . 
         [0044]    The release mechanism  5  is operatively mounted on the foldable upper frame  10  and associates with the pair of lockable articulated arms  2  so as to actuate the folding of the collapsible wheeled frame  1  and the foldable upper frame  10 . 
         [0045]    Preferably, the release mechanism  5  may include resilient member  50 , a slidable driving member  51 , a first connecting member  52 , a driving member  53 , a driven member  54 , a slider  55 , and a second connecting member  56 . 
         [0046]    The slidable driving member  51  is slidably mounted on the push arm  110  and associated with the driving member  53  via the first connecting member  52 . The first connecting member  52  is threaded through the push arm  110  and has a lower end which is slidably engaged with a skewed guiding slot  531  formed in the driving member  53 . 
         [0047]    Each joint  100  may pivotally couple with the mount  41  and forming a space for receiving the resilient member  50 , the driving member  53 , and the driven member  54 . The driving member  53  has a skewed guiding slot  531 , and has an out side for slidably engaging between the mount  41  and the joint  100  in a locked position. 
         [0048]    Referring to the  FIG. 5 , the inner periphery of the mount  41  is formed with a plurality of positioning slots  412  for selectively engaging with the outside of the driving member  53 . The driving member  53  is biased by the resilient member  50  and kept in the locked position thereby to lock the joint  100  in an un-rotatable position. 
         [0049]    When the first connecting member  52  is pulled upwardly by the slidable driving member  51 , the end portion of the first connecting member  52  is sliding along the skewed guiding slot  531 , the forces the driving member  53  moving against the biasing of the resilient member  50  thereby to disengage from the positioning slots  412 , so as to unlock the joint  100 . While the joint  100  is unlocked, the push arm  110  is freely to rotate either upwardly or downwardly. 
         [0050]    Referring to the  FIGS. 3 ,  4  and  6 , the driven member  54  has one side un-rotatably and retractably engaged with the driving member  53  and another side formed with a ramp  541 . The slider  55  is movably received in the mount  41  and passes through the upper end of the U-shaped arm  40 . 
         [0051]    The slider  55  has one end kept slidably abutted on the ramp  541  by a resilient member (not shown), and another end connected with the second connecting member  56 . When the joint  100  is unlocked, the driven member  54  is following the rotation of the push arm  110  and the driving member  53 , and then the ramp  541  of the driven member  54  drives the slider  55  to move in a direction of pulling the second connecting member  56  upwardly to unlock the pair of lockable articulated arms  2 . 
         [0052]    Referring to the  FIG. 7 , the pair of lockable articulated arms  2  includes a front arm  21 , a rear arm  22 , and a lockable joint  8 . The lockable joint  8  is pivotally connected the front arm  21  and the rear arm  22  and has locked position for preventing the rotation therebetween. 
         [0053]    The lockable joint  8  may simply comprises a latch member  81  and a resilient member  82 . The latch member  81  is operatively mounted in the front arm  21  and has one end connect with the second connecting member  56  and biased by the resilient member  82  to latch the rear arm  22  with the opposite end thereof. When the second connecting member  56  is pulled upwardly, the latch member  81  is driven to unlatch the rear arm  22 , and thereby to unlock the pair of lockable articulated arms  2  into a rotatable position. 
         [0054]    Alternatively, the lockable joint  8  may further to embody with a first joint member  83  and a second joint member  84  pivotally connected the first joint member  83 , using the first joint member  83  to connect with the front arm  21 , and using the second joint member  84  to connect the rear arm  22 . The latch member  81  may retractably mounted in the first joint member  83  and configured to be engagable with the second joint member  84 . When the second connecting member  56  is pulled upwardly, the latch member  81  is driven to disengage from the second joint member  84 , so as unlocks the pair of lockable articulated arms  2 . 
         [0055]    Referring to the  FIG. 9 , the front arm  21  is pivoted with the front strut  11 , and the rear arm  22  is pivoted with the rear strut  12 . When lockable joint  8  is kept in the locked position, the collapsible wheeled frame is kept in an erected position; however, when the joint  100  is unlocked, the push arm  110  can be rotate downwardly, this causes the second connecting member  56  to unlock the pair of lockable articulated arms  2 , so as to allow the front strut  11  and the rear strut  12  to rotate to close to each other as shown in the  FIG. 10 . 
         [0056]    Referring to the  FIG. 11 , the latch member  81  is alternatively connected with the first connecting member  52  that can be driven by either the slidable driving member  51  or a one-hand controllable folding actuator as disclosed in U.S. Pat. No. 6,443,479. 
         [0057]    Referring to  FIGS. 13 and 14 , an alternative embodiment of the collapsible wheeled frame  1  may comprise at least a front strut  11 , a pair of rear struts  12 , and a lockable swivel base  15  pivotally connected with the front strut  11  and the rear struts  12 . The lockable swivel base  15  includes an abutting slider  16  biased by a resilient member  17  to block the rotation path of the front strut  11  and the rear struts  12  thereby to fix the front strut  11  and the rear struts  12  in a using configuration. 
         [0058]    A foldable upper frame  10  is pivotally connected and supported by the lockable swivel base  15 . The foldable upper frame  10  may include a swivel rack  4 , a push arm  110 , and a pair of joints  100 . The pair of joints  100  are lockable and pivotably connect between the swivel rack  4  and the push arm  110 . 
         [0059]    The release mechanism  5  is operatably mounted on the foldable upper frame  10  for releasing the front strut  11  and the rear struts  12  from the using configuration by pulling the abutting slider  16  against the biasing of the resilient member  17 . As illustrated in  FIG. 15 , when the abutting slider  16  is pulled to leave the rotation path of the front strut  11  and the rear struts  12 , the front strut  11  and the rear struts  12  is permitted to rotate relative to each other, and ultimately, folded into a folded configuration. 
         [0060]    Referring to  FIGS. 14 to 16 , the release mechanism  5  associates with the abutting slider  16  by the second connecting member  56 . When joints  100  and  101  are unlocked, and the push arms  110  of the foldable upper frame  10  is rotated downwardly, the release mechanism  5  drives the second connecting member  56  to pull the abutting slider  16 , to actuate the folding of the collapsible wheeled frame  1 . 
         [0061]    Referring to  FIGS. 16 and 17 , a positioning member  58  is operatively mounted in the lower end of the swivel rack  4  for retractably engaging with the lockable swivel base  15  thereby to fix the direction of the foldable upper frame  10 . A resilient member  59  biased against the positioning member  58  to engage with the lockable swivel base  15 . 
         [0062]    Preferably, the lockable swivel base  15  is formed with indents  151  and  152  for engaging with the positioning member  58  for fixing the direction of the foldable upper frame  10 . 
         [0063]    Referring to  FIG. 18 , the release mechanism  5  may comprise a third connecting member  57  associated with the positioning member  58 . When joints  100  and  101  are unlocked, and the push arms  110  of the foldable upper frame  10  is rotated upwardly to a upright position, the release mechanism  5  drives the third connecting member  57  to pull the positioning member  58 , to disengage the positioning member  58  form the lockable swivel base  15 . 
         [0064]    While the invention has been described by way of example and in terms of preferred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.