Abstract: A foldable tricycle includes a center frame, a front frame to which a front wheel is rotatably attached, a rear frame to which two rear wheels are rotatably attached, and a four-bar link including a first bar that is integrated with the front frame, a second bar that is integrated with the center frame, a third bar that is integrated with the rear frame, and a fourth bar. The fourth bar has a shape of plates and covers the other bars while the link operates between an unfolded position and a folded position. Lockers that locks the link in either the unfolded position or the folded position are provided and include a pin, two recesses that receives the pin, and a tension spring that presses the pin into the recesses. A semi-circle guide guides the pin between the two positions and also covers the third bar.

Abstract: A foldable tricycle includes a center frame, a front frame to which a front wheel is rotatably attached, a rear frame to which two rear wheels are rotatably attached, and a four-bar link including a first bar that is integrated with the front frame, a second bar that is integrated with the center frame, a third bar that is integrated with the rear frame, and a fourth bar. The fourth bar has a shape of plates and covers the other bars while the link operates between an unfolded position and a folded position. Lockers that locks the link in either the unfolded position or the folded position are provided and include a pin, two recesses that receives the pin, and a tension spring that presses the pin into the recesses. A semi-circle guide guides the pin between the two positions and also covers the third bar.