Patent ID: 6951342

Claim:
A stroller comprising: a leg unit; a seat frame mounted on said leg unit; a backrest including a backrest frame that is pivoted to said seat frame and that extends upwardly and rearwardly therefrom in a longitudinal direction, said backrest frame being rotatable frontwardly and rearwardly relative to said seat frame about a first axis; a pivot pin unit; a positioning mechanism including an elongated positioning base that is pivoted to said leg unit through said pivot pin unit so as to permit rotation of said positioning base relative to said leg unit about a second axis parallel to said first axis, that extends upwardly and frontwardly from said pivot pin unit, and that is movably connected to said backrest frame, said positioning mechanism further including an elongated rail unit that is disposed between said positioning base and said backrest frame, that is secured to said backrest frame, and that extends in said longitudinal direction, a slide unit that is mounted slidably on said rail unit and that defines a sliding contact face which is in sliding contact with said rail unit and which is spaced apart from said backrest frame, a first engaging unit secured to said positioning base, a second engaging unit secured to said backrest frame and projecting therefrom toward said first engaging unit, and a pushing unit secured to and projecting from said slide unit to slidingly engage said positioning base so as to rotate said positioning base about said second axis during sliding movement of said slide unit on said rail unit, said slide unit is slidable on said rail unit in said longitudinal direction between an engaging position, in which said second engaging unit releasably engages said first engaging unit, thereby preventing rearward rotation of said backrest frame relative to said seat frame, and a disengaging position, in which said second engaging unit disengages from said first engaging unit, thereby permitting rearward rotation of said backrest frame relative to said seat frame; a control unit including a string that has an end connected to said slide unit and that is operable to pull said slide unit to move from said engaging position to said disengaging position; and an urging unit that is sleeved around said pivot pin unit so as to constantly urge said positioning base in a downward direction and so as to prevent undesired disengagement between said first and second engaging units.