Patent Publication Number: US-7900952-B2

Title: Folding stroller including locking mechanism

Description:
BACKGROUND 
     Exemplary embodiments of this invention relate to folding strollers which, when in a folded state, occupy a small volume of space and allow for easy transport and storage. 
     Related art folding strollers have been developed to increase portability by reducing a volume of space occupied by the stroller when in its folded state. Reducing the volume of space occupied by the stroller in a folded state allows the stroller to be more easily handled by a user, decreases the amount of space required for storage when not in use and allows for easy transportability by allowing the folded stroller to be easily placed in the trunk of a car, for example. Reduced volume also decreases shipping costs, which is helpful in an era when manufacturing facilities are located globally and individuals utilize the internet to purchase goods. 
     Related art folding strollers may have a problem that the length of the stroller in its folded state is the same or even greater than when in its unfolded state. 
     A related art stroller, known popularly as the MacLaren stroller and disclosed in U.S. Pat. No. 3,736,021 includes upper and lower X-shaped frame members which allow substantially identical side and leg members to be collapsed to reduce the stroller&#39;s width. However, when in a folded state, the length of the stroller increases when the front wheel assembly is pivoted in a direction away from the rear wheels. Also, because the handle portion is pivoted towards the front wheels and extends past the front wheels, the length is extended even more. This increased length in the folded state makes it difficult to store, handle, and transport the stroller. Additionally, the overall cost of the product may be increased due to increased shipping costs. 
     SUMMARY 
     Exemplary embodiments of this invention may include apparatus and methods that provide a stroller with enhanced portability, that occupies a small volume of space when in a folded state and that is easily handled by a user. 
     A stroller according to an exemplary embodiment includes two front legs and two rear legs that support the stroller in an upright position, two handle frames, and two first upper sliders that slide along respective handle frames. An upper X frame includes two upper frame members that are pivotally connected to each other at respective intermediate portions. Each upper frame member is pivotally connected to respective first upper sliders and to respective rear legs. Two second lower sliders slide along respective front legs. A lower X frame member includes two lower frame members pivotally connected to each other at respective intermediate portions. Each lower frame member is pivotally connected to respective second lower sliders and attached to respective rear legs. Two pivot frames are linked to respective second sliders and pivotally attached to respective rear legs. A pair of wheels are rotationally attached to the front legs, and a pair of wheels are rotationally attached to the rear legs. 
     A stroller according to an exemplary embodiment includes lower frame members with engaging portions that engage a respective rear leg to reduce the likelihood or prevent the stroller from folding and to provide lateral rigidity. 
     A stroller according to an exemplary embodiment includes two back frames, two lateral portions rotationally attached to respective back frames and to respective lower legs, and a seat portion supported by the back frames and the lateral portions. 
     An exemplary embodiment includes a stroller including two handle frames, two front legs and two rear legs that support the stroller in an upright position. Front legs are pivotally attached to respective rear legs. A chair portion, includes a back rest, a seat, and a leg rest pivotally attached to the seat. Two pivot frames are pivotally attached to respective handle frames. The back rest and the rear legs, two arm rests and two sliders are pivotally attached to respective pivot frames. The back rest, respective arm rests, and the seat slide along the respective front legs. Wheels are rotationally attached to the front legs and the rear legs. 
     An exemplary embodiment includes a stroller including a pre-load mechanism with a suspension pivotally attached to at least one of the front and rear legs and supporting an axle of a wheel. A resilient member, such as a spring, is attached at one end of the suspension, and a cam is attached to another end of the resilient member and pivots to compress the resilient member. 
     An exemplary embodiment includes a lock release mechanism configured to retain the stroller in a rigid unfolded state when locked and allow the stroller to be collapsed when released. The lock release mechanism may include a two step release mechanism. 
     An exemplary embodiment includes a stroller including arm rests with an attachment portion to allow an item to be attached to the arm rests. The attachment portion may include for example, one of a slot or tab and an item to be attached may include the other of a slot or a tab. The item to be attached may be a cup holder, a tray and/or a toy or any other suitable item. 
     An exemplary embodiment includes a pivot lock pivotally connected to a handle portion and a pivot lock lip, and a lip portion that engages with the pivot lock lip to maintain the stroller in a folded state. The pivot lock may be a tray including a tray portion and arm portions and the lip portion may be located on a foot rest. 
     An exemplary embodiment includes a seat belt tensioner for a seat belt, wherein a back rest includes through-holes through which a seat belt is passed. The belt is retained by a locking portion at one end and another end of the seat belt is attached to an underside of the seat. When the folding chair is in a folded state, the locking portion is pulled toward the back rest. 
     An exemplary embodiment includes a back rest with an adjustable incline so that when the folding chair is folded and unfolded the back rest is retained at its adjusted incline. 
     An exemplary embodiment includes a method of folding a stroller including two front legs and two rear legs that support the stroller in an upright position, two handle frames, and two first upper sliders that slide along respective handle frames, an upper X frame including two upper frame members pivotally connected to each other at respective intermediate portions, each upper frame member pivotally connected to respective first upper sliders and to respective rear legs, two second lower sliders that slide along respective front legs, a lower X frame member including two lower frame members pivotally connected to each other at respective intermediate portions, each lower frame member pivotally connected to respective second lower sliders and attached to respective rear legs, and two pivot frames linked to respective second sliders and pivotally attached to respective rear legs. The method includes detaching the two lower frame members from respective rear legs. A top portion of the handle frames is pivoted toward the front of the stroller. First upper sliders slide upward along respective handle frames and second lower sliders slide downward along respective front legs so that handle frames, front legs and rear legs become substantially parallel. The upper frame member and the lower frame members are collapsed about the respective intermediate pivot points so that the two handle frames move toward each other, the two front legs move toward each other and the two rear legs move toward each other. 
     Exemplary aspects of the invention provide a method of folding a stroller including two handle frames, two front legs and two rear legs configured to support the stroller in an upright position, the front legs pivotally attached to respective rear legs, a chair portion, including a back rest, a seat and a leg rest pivotally attached to the seat, two pivot frames pivotally attached to respective handle frames, the back rest and the rear legs, two arm rests, and two sliders pivotally attached to respective pivot frames, the back rest, respective arm rests and the seat and the two sliders are configured to slide along the respective front legs. The method includes pivoting a top portion of the handle frames toward a front of the chair. The handle frames are pivoted toward the front of the chair. The sliders slide downward along the leg. The rear legs are pivoted toward the front legs. The backrest is pivoted toward the front of the chair and the leg rests toward a rear of the chair. The handle frames, the slider, the front and rear legs, the backrest and the leg rest become substantially parallel in their length directions. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various exemplary embodiments will be described in detail, with reference to the following figures, wherein: 
         FIG. 1  is schematic side view of a first exemplary embodiment of a stroller in a completely unfolded state; 
         FIG. 2  is a schematic side view of the first exemplary embodiment of the stroller of  FIG. 1  when beginning to be placed in a folded state; 
         FIG. 3  is a schematic side view of the first exemplary embodiment of the stroller of  FIG. 1  in a folded state; 
         FIG. 4  is a schematic front view of the first exemplary embodiment of the stroller of  FIG. 1  in a completely unfolded state; 
         FIG. 5  is a schematic rear view of the first exemplary embodiment of the stroller of  FIG. 1  in a completely unfolded state; 
         FIG. 6  is a schematic side view of a second exemplary embodiment of a stroller in a completely unfolded state; 
         FIG. 7  is a schematic side view of the second exemplary embodiment of the stroller of  FIG. 6  when beginning to be placed in a folded state; 
         FIG. 8  is a schematic side view of the second exemplary embodiment of the stroller of  FIG. 6  in a partially folded state; 
         FIG. 9  is a schematic side view of a second exemplary embodiment of the stroller of  FIG. 6  in a completely folded state; 
         FIG. 10  is a schematic front view of the second exemplary embodiment of the stroller of  FIG. 6  in an unfolded state; 
         FIG. 11  is a schematic front view of the second exemplary embodiment of the stroller of  FIG. 6  when beginning to be placed in a folded state; 
         FIG. 12  is a schematic detail of an arm rest according to an exemplary embodiment including an attachment portion; 
         FIG. 13  is a schematic of a pivot lock according to an exemplary embodiment; 
         FIGS. 14A and 14B  are schematics of an arm rest including an abutment portion according to an exemplary embodiment; 
         FIGS. 15A and 15B  are schematics of a pre-load mechanism according to an exemplary embodiment; 
         FIG. 16  is a schematic of a rigid memory back according to an exemplary embodiment; 
         FIG. 17  is schematic side view of an exemplary embodiment of a stroller in a completely unfolded state; 
         FIG. 17A  is a view of a portion of the stroller of  FIG. 17 ; 
         FIG. 18  is a view of a portion of the stroller of  FIG. 17 ; 
         FIG. 19  is a sectional view of a portion of the stroller of  FIG. 17 ; and 
         FIG. 20  is a schematic view of a portion of the stroller of  FIG. 17  in a slightly folded state. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
       FIG. 1  illustrates a side view of a first exemplary embodiment of a stroller in a completely unfolded state. For purposes of clarity to show the elements of the stroller, the sling seat portion of the stroller is not shown in  FIGS. 1-4 . It should be appreciated by one of ordinary skill that in the following description some components of the stroller are provided in pairs and are identically situated on each side of the stroller. One of ordinary skill should appreciate that although the figures and following description are directed to a stroller the features of the example embodiments may be utilized in any folding chair. 
     Stroller  1  includes a handle portion  6  located at an end of a handle frame  9 . At an end of handle frame  9  opposite from the handle  6 , pivot frame  18  is rigidly attached. A portion of handle frame  9  protrudes past pivot frame  18  and is pivotally connected to an end of rear leg  14 . An end of rear leg  14 , opposite to the end pivotally connected to handle frame  9  has rear wheels  3  rotationally attached. An intermediate portion of rear leg  14  is pivotally attached to one end of front leg  12 . An end of front leg  12 , opposite to the end pivotally attached to rear leg  14  has front wheels  2  rotationally attached. 
     Stroller  1  includes sliders  16 A,  16 B. Slider  16 A is slidably attached to handle frame  9 . According to an example embodiment, slider  16 A has a cylindrical opening through which handle frame  9  is inserted so as to be surrounded by slider  16 A. One of ordinary skill would readily appreciate that slider  16 A may be configured in any suitable manner to slide or move relative to handle frame  9 . In a non-limiting example, handle frame  9  may be configured with a groove while slider  16 A is configured with a slot or pin that slides within the groove of handle frame  9 . 
     Slider  16 A is pivotally attached to one end of frame members  50 A,  50 B of upper X frame  50 . Frame members  50 A and  50 B are pivotally attached to each other at an intermediate connection point to form a substantially X shaped frame when the stroller is in a completely unfolded state. The end of each frame member  50 A,  50 B, opposite to the end pivotally attached to respective slider  16 A, is pivotally attached to an intermediate portion of respective rear leg  14 . 
     Slider  16 B is slidably attached to front leg  12 . According to an example embodiment, slider  16 B has a cylindrical opening through which front leg  12  is inserted so as to be surrounded by slider  16 B. As discussed with reference to slider  16 A above, one of ordinary skill would readily appreciate that slider  16 B may be configured in any suitable manner to slide or move relative to front leg  12 . 
     Slider  16 B is pivotally connected to one end of side frame  8 . An end of side frame  8 , opposite to the end connected to slider  16 B, is pivotally attached to pivot frame  18 . Sling seat (not shown) may be attached to a slider  16 A. An intermediate portion of side frame  8  is pivotally connected to lateral portion  19 . Lateral portion  19  provides support for a seat portion of a seat disposed on stroller  1 . Slider  16 B is pivotally connected to one end of frame members  52 A,  52 B of lower X frame member. Frame members  52 A and  52 B are pivotally attached to each other at an intermediate connecting portion to form a substantially X shape when in a completely unfolded state. The end of each frame member  52 A,  52 B opposite to the end pivotally connected to slider  16 B is attached to an intermediate portion of rear leg  14 , by leg support  54 . In a non-limiting example, leg support  54  has grooves which in the completely unfolded state of stroller  1  retain rear leg  14 . One of ordinary skill would readily appreciate the leg support  54  may have multiple configurations so long as leg support  54  may be attached to rear leg  14  to maintain stroller  1  in a rigid state and to prevent the stroller from inadvertently moving to a folded state. 
     An operation to fold stroller  1  will be described with reference to  FIGS. 1 and 2 . Handle frame  9  is pivoted in a direction as shown by arrow D. By pivoting handle frame  9 , pivot frame  18  rotates at its pivot point in a direction as shown by arrow E. Through its connection to pivot frame  18 , rear leg  14  pivots in a direction toward front wheels  2 , as shown by arrow C. As rear legs  14  pivot, leg support  54  is allowed to disengage from rear legs  14 . Leg support  54 , when engaged with rear legs  14  prevents frame members  52 A,  52 B from being collapsed toward each other. When leg support  54  is disengaged from rear leg  14 , frame members  52 A,  52 B may be collapsed toward each other around their intermediate connection point so that they move toward being substantially parallel. As frame members  52 A and  52 B collapse toward each other, the first and second halves of the stroller move toward each other to narrow the width of the stroller. 
     As handle frame  9  is pivoted in a direction shown by arrow D, slider  16 A travels toward handle  6 . Frame members  50 A and  50 B, pivotally attached to slider  16 A, collapse toward each other around their intermediate connection point so they move toward being substantially parallel. As pivot frame  18  pivots, slider  16 B is pushed along front legs  12  toward front wheels  2 , through side frame  8  as shown by arrow B. As slider  16 B moves toward front wheels  2 , frame members  52 A and  52 B are collapsed toward each other through their respective pivotal connection to slider  16 B. 
     In a completely folded state, as shown in  FIG. 3 , rear wheels  3  move towards the front wheels  2  and are not located on opposites sides of the length of the stroller as in the related art described above. Frame members  50 A,  50 B are collapsed toward each other to reduce the width of the stroller  1 . Front leg  12 , rear leg  14 , handle frame  9 , side frame  8 , and lateral portion  19  become substantially parallel to provide a folded stroller  1  which occupies a small volume of space in a length as well as in a width direction. 
       FIG. 6  is a schematic side view of a second example embodiment of a stroller in a completely unfolded state. Stroller  2  includes a handle portion  106  located at an end of handle frame  109 . As shown in  FIG. 13 , pivot lock  120  is pivotally attached to handle portion  106 . According to an example embodiment, when stroller  2  is in the unfolded state, pivot lock  120  hangs with tray  121  in a substantially horizontal state. Tray  121  may be provided in the form of a storage place such as a cup holder. Pivot lock  120  includes pivot lock lip  146 . When stroller  2  is placed in a completely folded state, the pivot lock  120  is pivoted so that the pivot lock lip  146  engages with a corresponding lip  144  located on a lower lateral portion of foot rest  104 . By engaging pivot lock lip  146  with lip  144 , the stroller  2  may be prevented from becoming unfolded. 
     At an end of the handle frame  109  opposite from the handle  106 , pivot frame  118  is rigidly attached. Rear leg  114  is pivotally attached to pivot frame  118  at one end. At an opposite end of rear leg  114  rear wheels  103  are rotationally attached. Back rest  108  is pivotally attached to front leg  112 . Slider  116  is pivotally attached to pivot frame  118 . An intermediate portion of slider  116  is pivotally attached to seat  107 . An end of the slider  116  that is opposite to the end pivotally attached to the pivot frame  118  is slidably attached to front leg  112 . According to an example embodiment, slider  116  has a cylindrical opening which surrounds front leg  112  and slides over front leg  112 . However, one of ordinary skill would appreciate that slider  116  may have multiple configurations to slide relative to front leg  112 . 
     Seat  107  includes two parallel lateral portions  119 . One end of lateral portion  119  is pivotally attached to leg rest  105 . An intermediate portion of lateral portion  119  is pivotally connected to an intermediate portion of slider  116 . An end of lateral portion  119  opposite to the end attached to leg rest  105  is pivotally attached to an intermediate portion of rear leg  114 . An optional basket  110  can be removably attached to the lateral portions  119 . 
     Front leg  112  is attached at one end to foot rest  104  and at an opposite end to rear leg  114  at an end of rear leg  114  that is opposite to the end that rear wheel  103  is attached to. The front wheels  102  may be rotationally attached to front leg  112 . 
     An operation to fold stroller  2  will be described with reference to  FIGS. 7-9 . As shown in  FIG. 9 , lock release  124  is located to be centered on the handle portion  106 . Lock release  124  includes a two step release mechanism. The first step, for example, a push button, allows the second step, for example, two spring loaded squeeze buttons, to be urged toward each other to release latch  122 . When latch  122  is released stroller  2  is able to be folded. It should be noted that a release mechanism is required under common safety standards. When latch  122  is in a latched position the stroller may maintain rigidity when in an unfolded state and accidental folding of the stroller when in use may be prevented. 
     Once the latch  122  has been released from a latched position, the stroller  2  may be folded. Handle frame  109  is pivoted toward the front of the stroller in a direction shown by arrow F in  FIG. 7 . Handle frame  109  is rigidly connected to pivot frame  118 . Thus, pivot frame  118  will also pivot forward as a result of handle frame  109  being pivoted forward as shown by arrow H. As pivot frame  118  is pivoted forward, slider  116  is urged forward through its pivotal connection to pivot frame  118 . As shown by arrow I, slider  116  will slide forward along front leg  112 . Slider  116  is pivotally connected at an intermediate portion to lateral portion  119 , which in turn is pivotally connected to rear leg  114 . As slider  116  slides forward along front leg  112 , rear leg  114  is pulled forward, as shown by arrow J, via lateral portion  119 . Back rest  118 , which is pivotally connected to front leg  112  also pivots forward. Leg rest  105  is pivotally connected to wire link  160 . Wire link  160  is pivotally attached to front leg  112 . 
     As handle frame  109  continues to pivot forward, the slider  116  slides along the remaining length of front leg  112 . As shown in  FIG. 9 , in a folded position, handle frame  109 , slider  116 , front leg  112 , lateral portion  119  and rear leg  114  are substantially parallel to each other along a length portion of each resulting in a folded chair that occupies a small volume of space, and is easy to handle, transport, and store. 
     As shown in  FIG. 13  when stroller  2  is in a folded state, pivot lock  120  is pivoted around handle  106  so that pivot lock lip  146  engages with lip  144  located on foot rest  104 . As discussed above this prevents the stroller  2  from becoming unfolded. 
     As shown in  FIG. 6 , arm rest  111  is pivotally attached to slider  116  at one end. As slider  116  slides forward along front leg  112 , arm rest  111  pivots toward slider  116 . In a folded state arm rest  111  is substantially parallel with slider  116  along the length portion of each. At an end of arm rest  111  opposite the end pivotally attached to the slider, there may be provided an arm rest accessory  140  which may be detachable from arm rest  111 . The accessory may be attached to the arm rest  111  in any suitable manner. In an example embodiment shown in  FIG. 12 , arm rest  111  is provided with a slot  142  through which arm rest accessory  140 , shown as a cup holder in  FIG. 12  is attached. One of ordinary skill would recognize that arm rest accessory  140  may be configured in any suitable manner, such as for example, a tray provided with slots for each arm rest  111 . As shown in  FIGS. 14A and 14B , arm rest  111  may include an abutment portion  115  which abuts against pivot frame  118  or in another example embodiment against handle frame  9 . 
     As shown in  FIGS. 15A and 15B , a pre-load mechanism  180  may be provided to adjust the ride characteristics of the stroller depending upon the weight of the object or person placed upon the stroller or a desired comfort level. Pre-load mechanism  180  includes a casing  181  with a hollow interior. Resilient member  182  is mounted to be compressible within the casing  181  via cam  183  which includes an abutment surface  184  which abuts one end of resilient member  182 . Cam  183  has a pivot handle  187  which is used to pivot cam  183  to compress or decompress resilient member  182 . An end of resilient member  182 , opposite the end that abuts abutment surface  184  of cam  183  is fixed to an intermediate portion of suspension  185 . Suspension  185  is pivotally attached at substantially one end to rear leg  114  and at an opposite end to rear axle  186  which supports rear wheels  103 . 
     An operation of the pre-load mechanism  180  will now be described. In an unloaded state, resilient member  182  is not compressed by action of cam  183 . Forces operating on rear wheels  103  are transmitted via axle  186  to suspension  185  which pivots about its pivotal connection with rear leg  114 . Resilient member  182  applies a load to suspension  185  which absorbs the forces operating on rear wheels  103  so they are not transmitted to an occupant of the stroller  2  to cause an uncomfortable ride. As an occupant of stroller  2  becomes heavier, resilient member  182  in its uncompressed state may be inadequate to absorb the forces acting on rear wheels  103 . By lifting handle  187 , cam  183  pivots and abutment portion  184  compresses resilient member  182 . In a compressed state, resilient member  182  may absorb forces acting on rear wheels  103  for a heavier load. 
     As shown in  FIG. 6 , seat  107 , backrest  108 , and leg rest  105  together provide the seat portion for an occupant of the stroller. Leg rest  105  is pivotally attached to seat  107 . Backrest  108  is pivotally attached to front leg  112 . Thus, the sitting position is configured in separate sections which may be foldable relative to each other. 
     Backrest  108  includes through-holes  136 , as shown in  FIG. 11 . Because seat  107 , backrest  108  and leg rest  105  are configured in separate sections, gaps  134  are formed between each section. Belt  130  is provided to retain an occupant of stroller  2  for safety purposes. As shown in  FIG. 10 , belt  130  includes belt lock  132  to fix the belt to retain an occupant. Belt  130  passes to a rear side of backrest  108  via through-holes  136  and then is passed under the backrest  108  and fixed to an underside of seat  107 . As the stroller  2  is moved to a folded state, belt  130  is pulled taut by a movement of seat  107 . Belt  130  is pulled from the rear of through-holes  136 . Belt  130  is prevented from completely passing through through-holes  136  by belt lock  132 , which is made larger than the through-holes  136 . In a folded state, belt lock  132  is held against backrest  108  and prevented from falling between gaps  134 . If belt lock  132  falls into gaps  134  it could become damaged due to compression between the folded portions of the stroller. 
     As shown in  FIG. 16 , backrest  108  includes a rigid memory back feature which provides backrest  108  with a set incline in an unfolded state, that after the stroller is folded and unfolded, maintains the backrest in the previously set incline. Backrest  108  includes a recline pivot bar  90  which supports backrest  108  from the rear. Recline pivot bar  90  passes through flanges  91 A,  91 B located to protrude rearwardly from backrest  108 . Flanges  91 A,  91 B are provided with through-holes which include adjustment grooves  92 . Recline pivot bar  90  is biased via a resilient member to engage with grooves  92  to provide recline positions for backrest  108 . Recline pivot bar  90  passes through flanges  91 A,  91 B and is pivotally attached to an end of link  93 . Another end of link  93 , opposite to the end attached to recline pivot bar  90  is pivotally attached to an intermediate portion of slider  116 . As pivot frame  118  pivots and slider  116  moves along front leg  112 , backrest  108  pivots while recline pivot bar  90  remains in engagement with a selected adjustment groove  92 . In a folded state, recline pivot bar  90  remains engaged with the selected adjustment groove  92 . When stroller  2  is returned to an unfolded state recline pivot bar  90  is still engaged with the selected adjustment groove  92  to provide the rigid memory back feature. 
     Another exemplary embodiment of a stroller is shown in  FIG. 17 . The embodiment shown in  FIG. 17  is similar to the embodiment shown in  FIGS. 1-5 . Therefore, duplicative descriptions will be omitted. 
     As shown in  FIG. 17  and as shown in greater detail in  FIG. 17A , a stroller  200  includes a handle  206  located at an end of a handle frame  209 . A lock release button  262  is positioned on the handle  206 . The lock release button  262  can have a button cover  264  positioned to prevent the lock release button  262  from being accidentally pressed. The button cover  264  can be rotated in the direction of arrow K in order to access the lock release button  262 . As shown in  FIG. 18 , the button cover  264  can include a cover member  266  that is attached to the handle  206  with a rivet  268 . Additionally, a spring  270  can bias the cover member  266  to a position covering the lock release button  262  to prevent the lock release button  262  from being accidentally pressed. 
     As shown in  FIG. 19 , the lock release button  262  is positioned on an end of a locking rod  300 . The locking rod  300  is located within the handle frame  209 . The locking rod  300  is movably positioned within the handle frame  209  via rivets  302 . The rivets  302  pass through holes  304  in the locking rod  300 . The holes  304  in the locking rod  300  are bigger than a diameter of the rivets  302  such that the locking rod  300  can travel a limited distance within the handle frame  209 . A compression spring  306  positioned at an end of the handle frame  209  opposite to the lock release button  262  provides a biasing force to the locking rod  300  such that the lock release button  262  returns to an extended state when the lock release button  262  is not being pressed. Additionally, a folding prevention pin  308  is attached to the locking rod  300  and extends outside of the handle frame  209 . 
     As shown in  FIG. 17A , a pivot frame  218  is rigidly attached at an end of the handle frame  209  opposite from the handle  206 . In an unfolded position, the pivot frame  218  abuts against a housing member  272  rigidly connected to an end of a side frame  208 . The housing member  272  includes a raised portion  274  which surrounds the folding prevention pin  308  when the stroller  200  is in the unfolded position such that the folding prevention pin  308  will contact the raised portion  274  if force is applied to the handle  206  or handle frame  209 . Thus, the raised portion  274  prevents the folding prevention pin  308  from moving in the folding direction and keeps the stroller  200  from being folded without the lock release button  262  being pressed. As a result, accidental folding of the stroller  200  can be prevented. 
     A process of unlocking of the stroller  200  in order to fold the stroller  200  will now be described. 
     In order to fold the stroller  200 , the lock release button  262  must be pressed. To access the lock release button  262 , the button cover  264  is rotated in the direction of arrow K to allow access to the lock release button  262 . Then, the lock release button  262  is pressed, pushing the locking rod  300  downward and compressing the compression spring  306 . When the locking rod  300  is pushed downward, the folding prevention pin  308  translates downward through an opening of the raised portion  274  of the housing member  272 . Thus, the folding prevention pin  308  is no longer surrounded by the raised portion  274  of the housing member  272 . 
     Next, while the folding prevention pin  308  is no longer surrounded by the raised portion  274 , the handle frame  209  is pivoted in a direction as shown by arrow D in  FIG. 17 . By pivoting the handle frame  209 , the pivot frame  218  rotates at its pivot point in a direction as shown by arrow E in  FIG. 20 . Thus, the pivot frame  218  is separated from the housing member  272 . Once the pivot frame  218  is separated from the housing member  272 , the lock release button  262  can be released. When the lock release button  262  is released, the biasing force from the compression spring  306  will cause the locking rod  300 , the folding prevention pin  308 , and the lock release button  262  to return to their original positions. However, because the pivot frame  218  was separated from the housing member  272 , the folding prevention pin  308  will not be restricted by the raised portion  274  of the housing member  272 , and the stroller  200  can continue to be folded. 
     The remaining steps for folding the stroller  200  are similar to those described with respect to  FIGS. 1-5 . Thus, the duplicative description will be omitted. 
     As can be seen in  FIG. 17 , the stroller  200  may include at least one rearward-facing cup holder  310 . Additionally, as described above, alternative accessories could be attached to the stroller  200  in place of the cup holder  310 . Further, a basket  320  can be removably attached to the stroller  200 . 
       FIG. 17  shows a lock release button  262  on each of the handles  206 . However, in an alternative embodiment, only one lock release button  262  may be provided. Additionally, while  FIG. 17  shows two handle frames  209 , the lock release button  262 , and the accompanying locking mechanism could be provided with a handle  106  similar to that described with respect to  FIG. 6 . 
     While this invention has been described in conjunction with exemplary embodiments outlined above, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments of this invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention.