Abstract: A tricycle has two non-steerable rear wheels connected to a rear frame structure, and a single steerable front wheel connected to a front frame structure. The front frame structure includes a horizontal tubular frame element extending underneath the rear frame structure for swingable connection to the rear frame structure, such that the front frame structure can lean away from a normal upright position centered between the rear wheels. During a turning maneuver the leaning capability is advantageous in maintaining the rear wheels in pressure contact with the road surface so as to enhance the stability of the tricycle. A manually-operated locking mechanism is provided for releasably locking the front frame structure in its normal upright centered position. The locking mechanism keeps the front frame structure in a stable mode when the person is mounting or dismounting the tricycle, and also when the tricycle is being driven at low speeds in which there is minimal danger of the tricycle tipping or overturning.

Abstract: A tricycle has two non-steerable rear wheels and a single steerable front wheel. One of the rear wheels is driven by a chain-sprocket drive system that includes a drive sprocket mounted on a front frame and a driven sprocket mounted on a rear frame. The front frame is tiltable, or swingable, from an upright position to a leaning position to minimize the potential for turnover of the tricycle during turning maneuvers or riding on rough terrain. Special idler sprockets are provided for the drive chain, to keep the chain in mesh with the drive sprocket when the front frame is in a leaning position.

Abstract: A tricycle (20) disclosed includes a front section (22) and rear section (24). The front section (22) is articulated with respect to the rear section (24) so that the front section (22) can be leaned with respect to the rear section (24) from a normal orientation to lean orientation. A caliper assembly (70) interconnects the front and rear sections (22,24) at the point of articulation and includes arms (72,74) which spread when the front section (22) is leaned with respect to the rear section (24). A biasing member (76) connected to the spreadable arms (72,74) biases the arms together to obviate lean orientation. The front section (22) includes a steerable drive wheel (42) including a hub (44), a central sprocket (34) spaced from the hub (44) and an endless belt (48) interconnecting the hub (44) with the sprocket (48) to provide front wheel drive unaffected by drive apparatus. Rear wheels (86,88) are adjustably spaceable by the movement of frame arms (82,84).