Patent ID: 8146937

Claim:
A twin-frame bicycle, comprising: a primary bicycle body, having a primary bicycle frame, a front wheel, a rear wheel and a pedal mechanism, wherein the front wheel and the rear wheel are connected rotatably to the primary bicycle frame and distanced from each other, and the pedal mechanism is used to drive the front wheel or the rear wheel; an auxiliary bicycle body, having an auxiliary bicycle frame and a first auxiliary wheel, wherein the first auxiliary wheel is connected rotatably to the auxiliary bicycle frame; at least one articulation mechanism, having a first end, a second end and at least two linking portions, wherein the first end and the second end are connected to the primary bicycle frame and the auxiliary bicycle frame, respectively, the linking portions are substantially disposed in parallel between the first end and the second end, and the first end, the second end and the linking portions forming a movable quadrangle; and a resilient tension mechanism, having an elastic element disposed between the primary bicycle body and the auxiliary bicycle body.