A folding frame for a tricycle, scooter or child's bicycle, with a front frame part on which the front wheels can be mounted at least indirectly, a rear frame part on which the rear wheels can be mounted, a swivelling joint with a front articulated part which is mounted on the front frame part, and with a rear articulated part which is mounted on the rear frame part, the first of the two articulated parts has a first recess and the second of the two articulated parts has a second recess and a third recess, the first recess and the second recess in the position of use of the frame are in alignment, and the first recess and the third recess in the folded position are in alignment, and the first articulated part and the second articulated part are locked against one another in the position of use and in the folded position via a pin which can be moved in the recesses.

A folding frame for a tricycle, scooter or child's bicycle has a front frame part on which the front wheels can be mounted and a rear frame part on which the rear wheels can be mounted. A swivelling joint with a front articulated part is mounted on the front frame part and a rear articulated part is mounted on the rear frame part. The first of the two articulated parts has a first recess and the second of the two articulated parts has a second and third recess. The first recess and the second recess are in alignment in the use position of use and the first recess and the third recess are aligned in the folded position. The first articulated part and the second articulated part are locked against one another in the use position and in the folded position via a pin which can be moved in the recesses.

Wheeled personal mobility vehicles with extremely thin stowed profiles are provided, which in one embodiment, include a plurality of movable, collapsible wheel axle assemblies which are supported on a support frame and movable between an operative state where the wheels provide rolling support, and a collapsed state where the wheels are moved into the side elevational profile of the device. The embodiment provides for both integrated propulsion and steering linkage to the wheels when they are manually moved into their operative position, along with a collapsible steering mechanism, a support base and at least one collapsible seat. This embodiment may also provide for pedal power, battery, fuel cell or motive power as well as remote control operation. Several alternative pedal or motive power, wheeled devices and tricycles collapse all parts into a thin, side elevational profile, and one alternative "tricycle" embodiment includes a multiple jointed "A-frame" embodiment incorporating folding handlebars as well as movable wheel axle assemblies which parts all fold into two or more parallel planes to provide for extremely thin, compact storage and/or transport. Various embodiments may include unique multi-function folding pedals which may be manipulated to provide for selective changing of gears, glide mode, as well as friction braking.

A vehicle frame assembly includes a forked first frame member coupled to a second frame member via a coupling device. The coupling device includes first and second tab units, and a fastening unit. The first tab unit is mounted on the first frame member, and includes a pair of first tabs, each formed with a first coupling hole and an angle-adjusting hole unit. The second tab unit is mounted on the second frame member, and includes a pair of second tabs, each formed with a second coupling hole and an engaging hole unit to be registered with the first coupling holes and the angle-adjusting hole units, respectively. The fastening unit includes a first fastener extended removably through the first and second coupling holes, and a second fastener extended removably through the angle-adjusting hole units and the engaging hole units.