Abstract: A caster switching mechanism for installation in a footboard of a scooter is used to control, through a switch pivotally connected with the footboard, whether a wheel seat is rotatable relative to footboard. When the switch is located at a restricted position where the wheel seat is stopped by the switch, the wheel seat is prohibited from rotation relative to the footboard such that a wheel that is rotatably mounted to the wheel seat can roll along one direction only. When the switch is located at an unrestricted position where the switch is separated from the wheel seat, the wheel seat is rotatable relative to the footboard such that the wheel can roll along any direction corresponding to the orientation of the wheel seat.

Abstract: A combination vehicle frame includes a base frame unit formed of a plurality of frame bars detachably connected to one another. One of the frame bars is provided with a head having intersected first through hole and second through hole. A rear wheel frame unit is detachably connected to the base frame unit remote from the head. A front wheel frame unit is selectively inserted through one of the first through hole and second through hole of the base frame unit.

Abstract: A combination vehicle frame includes a base frame unit formed of a plurality of frame bars detachably connected to one another. One of the frame bars is provided with a head having intersected first through hole and second through hole. A rear wheel frame unit is detachably connected to the base frame unit remote from the head. A front wheel frame unit is selectively inserted through one of the first through hole and second through hole of the base frame unit.

Abstract: A vehicle includes a chassis, a transmission shaft, a linkage, and a seat. The chassis has two front wheel units pivotally mounted thereto. The transmission shaft is rotatably mounted to the chassis. The linkage is connected between the transmission shaft and the two front wheel units for turning the two front wheel units upon rotation of the transmission shaft. The seat is fixedly mounted on the transmission shaft for the user sitting thereon to turn the transmission shaft and to further turn the two front wheel units relatively to the chassis.