Abstract:
A joint structure for a baby stroller comprises a articulated assembly connected to the rear leg tube of the stroller frame, and uses the articulated assembly controllable pivoted with the push bar and the front leg tube. The articulated assembly has an engaging pin for locking the push bar in a fixed position therefore to keep the stroller in a erected position. The engaging pin may pulled and disengaged from the end of the pull bar, and allows the push bar to rotate to collapse the stroller.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a joint structure for a walking aid, and more particularly, to a joint structure which can be operated between a collapsed position and an erected position. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    Baby strollers usually provide with a frame capable of being extended in an expanded position for carrying babies and of being folded in a collapsed position. In order to control the operation of the baby stroller, an articulated device for folding the stroller frame is needed. The articulated device on a collapsible stroller normally includes a push bar connected with a upper joint element at its end portion, and a lower joint element provided with a locking notch and firmly attached to the upper end of a front leg tube. The push bar is slidably received a connecting rod for driving a latch element for latching in and getting back from the locking notch of the lower joint element. When the latch element is latched in the locking notch, the stroller is fixed in an expanded position, and if the latch element is pulled by the connecting rod and left from the locking notch, the stroller is recovery from the expanded position to a collapsed position for easy transportation and saving space. 
         [0003]    The forementioned structure of the commercial available stroller has not enough strength, because the connection point between the push bar and front leg tube is only achieved by the latch element and the locking notch, thus easily causes a damage on the lower joint element and may abruptly and erroneously dismantled and folded to hurt the child therein. 
         [0004]    Another related structure in the prior art as disclosed in the U.S. Pat. No. 5,605,049 uses a slidably upper joint engageable with the upper end of the front leg tube, for fixing the stroller in a erected position to provide a better strength for the structure. However, before engaging the slidably upper joint to the front leg tube, the user is needed to align the slidably upper joint parallel to the front leg tube carefully, or the engagement may not be fully accomplishd. 
       SUMMARY OF THE INVENTION 
       [0005]    In order to improve the stroller frame and avoid the problems about the structure strength, the present invention provides a new structure of a stroller frame, comprises a articulated assembly connected to the rear leg tube of the stroller frame, and uses the articulated assembly controllable pivoted with the push bar and the front leg tube. 
         [0006]    The articulated assembly has an engaging pin for locking the push bar in a fixed position therefore to keep the stroller in a erected position. The engaging pin may be pulled and disengaged from the end of the pull bar, and allows the push bar to rotate to collapse the stroller. As the pushed bar is locked at the end, there can be obtained a good support strength and easy to accomplish a good smooth operation by user. 
         [0007]    Additional objects and advantages of the invention will be set forth in the following description and it is easy for a person having ordinary skill in this art to infer other variations from above illustrations and embodiments. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
           [0009]      FIG. 1  is a side view of a embodiment of the present invention showing an articulated assembly connected to the rear leg tube and pivotally connected with the push bar and the front leg. 
           [0010]      FIG. 2  is an exploded view of an embodiment of the articulated assembly according to the present invention. 
           [0011]      FIG. 3  is a schematic perspective view showing the position of an engaging pin in a engaged position that limited the push bar from rotation and fixed the stroller frame in an erected position. 
           [0012]      FIG. 4  is a schematic perspective view showing the engaging pin slidably received within a positioning bracket and guided by a slot thereof. 
           [0013]      FIG. 5  is an enlarged schematic view showing a locking mechanism limited the folding between the upper portion and lower portion of the push bar. 
           [0014]      FIG. 6  is an enlarged schematic view showing the locking mechanism released the limitation of the folding between the upper portion and lower portion of the push bar. 
           [0015]      FIG. 7  is an enlarged schematic view showing the engaging pin limited the rotation of the push bar. 
           [0016]      FIG. 8  is an enlarged schematic view showing the engaging pin dismissed the limitation, and allows the push bar rotated to an angle. 
           [0017]      FIG. 9  is a schematic view showing the engaging pin slidably moved to dismiss the limitation, and allows the push bar to rotate to an angle. 
           [0018]      FIG. 10  is a schematic side view showing the directions of folding the stroller of the present embodiment. 
           [0019]      FIG. 11  is a schematic side view showing the folding status the stroller of the present embodiment. 
           [0020]      FIG. 12  is a schematic side view showing an alternative embodiment according to the present invention. 
           [0021]      FIG. 13  is a schematic side view showing another alternative embodiment according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    Referring to  FIGS. 1 to 4 , an embodiment of the present invention comprises an articulated assembly  20  controllably equipped on a stroller frame  10  stroller frame  10  has a front leg tube  11 , rear leg tube  12  and a push bar  13 . 
         [0023]    The upper end of the front leg tube  11  connected with a lower holding element  111  and a connecting element  14 . The lower holding element  111  may be a U-shaped bracket and made of metal or high strength engineering plastic. The lower connecting element  14  is pivotally connected between the front leg tube  11  and the push bar  3  either directly or indirectly. 
         [0024]    The push bar  13  includes a upper portion  131 , a lower portion  132  a locking mechanism  133 , a upper holding element  134  and a hooked element  137 . The locking mechanism  133  is provided for controllably connecting the upper portion  131  and the lower portion  132 . The hooked element  13  is removably connected with the upper holding element  134  and having a connecting means (not shown) connected with the locking mechanism  133 . 
         [0025]    The end of lower portion  131  of the push bar  13  is formed with a slot  135  and connected with the upper holding element  134  and the connecting element  14 . The upper holding element  134  has a slot  135   a  and an abutting edge  136 , said slot  135   a  is aligned with the slot  135  of the end of lower portion  131  for receiving and guiding a pin for reciprocally sliding therein. 
         [0026]    The articulated assembly  20  is connected to the upper end of the rear leg tube  12  and includes a positioning bracket  2 , a engaging pin  3  and a release device  4 . The positioning bracket  2  is formed with a pair of side walls  21 , a slot and a positioning notch  23 . Between the pair of side walls  21 , positioning bracket  2  pivotally connects the front leg tube  11  and the push bar  12 , thus allows the front leg tube  11  and the push bar  12  can be rotated to close to each other. Preferably, for safety, a cover is provided to cover on the outside of the positioning bracket  2 , to prevent a user&#39;s finger grabbed in and accidentally hurt by the rotation of tubes 
         [0027]    The engaging pin  3  connects with a slider  31 , a resilient element  32  and a extended portion  311 . The engaging pin  3  is slidably connected between the pair of side walls  21  of the positioning bracket  2 , and guided by the slots  22  on the side walls  21 . In the present embodiment, the slider  31  is slidably received within positioning bracket  2  and biased by the resilient element  32  and kept the engaging pin  3  abutted against the upper end of the slots  22  of the positioning bracket  2 . 
         [0028]    While the stroller frame  10  is erected, the engaging pin  3  limits the rotation of the push bar  13  by moving into the position contacted with the abutting edge  136  of the upper holding element  134 . 
         [0029]    The release device  4  includes a driving element  41 , a connecting element  42  and a resilient element  43 . The driving element  41  has arched slot  411  and a pin hole pivotally connected in the lower portion  132  of the push bar  13 . The connecting element  42  movably received in the lower portion  132  of the push bar  13 , has a free end  421 , an extending tab  422 , skewed slot  423 , positioning pin  424  and a resilient element  425 . 
         [0030]    The resilient element  43  has one end connected with the inside of the lower portion  132  of the push bar  13 , and one end connected with the connecting element  42  for biasing the free end  421  abutting the inside of the locking mechanism  133 . 
         [0031]    The extending tab  422  is formed on the other end of the connecting element  42  and pivoted with driving element  41  via the skewed slot  423 . The positioning pin  424  is laterally extending from the end of the connecting element  42  and movably biased by the resilient element  425  for engaging into the positioning notch  23  of the positioning bracket  2 . 
         [0032]    As shown in  FIG. 5 , when the stroller frame  10  is in an erected position, the locking mechanism  133  is locked the upper portion  131  and lower portion  132  in a substantially straight configuration. 
         [0033]    Referring again to  FIG. 1 , a user can fold the stroller frame  10  by pull the hooked element  137  to slide along the upper portion  131  of the push bar  13  and release the locking mechanism  133  from the locked position. When the locking mechanism  133  is released, the upper portion  131  is rotatable to close to the lower portion  132 . 
         [0034]    Referring to  FIG. 6 , when the upper portion  131  is rotated and closed to the lower portion  132 , the free end  421  of the connecting element  42  is departed from the end of the upper portion  131  and moved upward by the biasing of the resilient element  43 . 
         [0035]    Referring to  FIGS. 7 and 8 , while the connecting element  42  is moving upward, the position pin  424  is leaving the positioning notch  23  of the positioning bracket  2 , and the skew  423  of the extending tab  422  forces the driving element  41  to rotate and press down the extended portion  311  of the engaging pin  3 . This makes the engaging pin  3  left the abutting edge  136  of the upper holding element  134 . When the engaging pin  3  left the abutting edge  136 , the lower portion  132  of the push bar  13  is rotatable to close the rear leg tube  12 . 
         [0036]    Referring to  FIG. 9 , when the push bar  13  is rotated, the connecting element  14  carries the front leg tube  11  to rotate toward the rear leg tube  12  as the arrows shown the directions in  FIG. 10  until the collapsed position shown in  FIG. 11 . 
         [0037]    Referring to  FIG. 12 , an alternative embodiment has a push bar  13  formed with an abutting edge  136 , connects a hooked element  5 , a driving element  41 , connecting element  42 , and a resilient element  43 . The main difference between the present embodiment and the previous embodiment is the handle bar  13  which equipped without the locking mechanism  133  as shown in  FIG. 10 . The hooked element  5  is movably connected with the push bar  13 . It is possible to drive a driving element  41  via such a connecting element  42  by pulling the hooked element  5  against the biasing force form a resilient element  43 . 
         [0038]    There is a further alternative embodiment as shown in the  FIG. 13 . In this alternative embodiment, the hooked element  5 , the connecting element  42 , the resilient element  43  are operatively connected with the rear leg tube  12 . The engaging pin  3  and the slider  31  are pulled by the hooked element  5  via the connecting element  42  when start to folding the stroller frame  10 . The user may drive the hooked element  5  by foot to start the folding operation. 
         [0039]    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.