Folding handlebar mechanism and folding vehicle having same

A folding handlebar mechanism comprising:

• a steering tube;
• a stem assembly mounted on the steering tube and including a plurality of gaps respectively formed at two distal ends thereof, two bilateral first guiding slots, and two bilateral second guiding slots faced and arranged opposite to the two first guiding slots, wherein the stem assembly includes an outer sleeve and an inner sleeve mounted into the outer sleeve, with the plurality of the gaps including two first gaps and two second gaps, with the outer sleeve including the two first gaps respectively formed at two distal ends thereof, with the inner sleeve including the two second gaps respectively formed at two distal ends thereof and corresponding to the two first gaps of the outer sleeve, the two bilateral first guiding slots, and the two bilateral second guiding slots;
• two handlebars each including an engaging portion and a gripping portion formed at two opposite ends thereof, with the engaging portion rotatably and slidably mounted into one of the two distal ends of the stem assembly and having a guiding hole;
• two guiding pins inserting through the two first guiding slots, the two guiding holes and the two second guiding slots;
• a repressed member abutted against the stem assembly;
• and
• a positioning assembly operable between a tighten mode and a loose mode and including a rod inserting through the stem assembly and the repressed member;
• wherein the positioning assembly in the tighten mode attaches and presses against the repressed member to secure the repressed member to the stem assembly to securely mount the two handlebars at the two opposite ends of the stem assembly and in the loose mode detaches from and does not press against the repressed member to allow the two handlebars to be rotatable and slidable with respect to the two opposite ends of the stem assembly.