Patent ID: 7341265

Claim:
A frame structure for foldable baby trailer comprising: a bottom frame, said bottom frame comprising two side bars horizontally arranged in parallel at two sides, a front bar and a rear bar connected between respective front and rear ends of said side bars, two wheel holder frames respectively affixed to said side bars to support a respective wheel, and a channel shaped lug affixed to the front end of one of said side bars at a bottom side, said channel shaped lug having a pair of front locating holes and a pair of rear locating holes; two arched vertical side frames respectively pivoted to said side bars of said bottom frame, said arched vertical side frames each having a lug respectively fixedly provided at a top side, the lugs at said arched vertical side frames each having a locating groove; a transverse top bar, said transverse top bar having two springy hooks respectively provided at two ends thereof and respectively detachably fastened to the locating grooves of the lugs at said vertical side frames; a trailer bar, said trailer bar having a rear end pivotally connected to said channel shaped lug at one of said side bars of said bottom frame by a pivot and a front end connectable to a bicycle or tricycle, said trailer bar being turned about said pivot between an extended position and a received position; and a lock pin selectively inserted into the front or rear locating hole of said channel shaped lug to lock said trailer bar to said bottom frame between said extended and said received position; wherein said vertical side frames each are comprised of an arched top frame bar and two bottom frame bars, said arched top frame bar having two distal ends thereof respectively pivotally connected to said bottom frame bars, said bottom frame bars each having a top end respectively pivoted to said arched top frame bar, a bottom end respectively pivoted to said side bars of said bottom frame, and a stop plate fixedly provided at the respective top end for stopping the associating arched top frame bar to limit the turning angle of the associating arched frame bar relative to the respective bottom frame bar; said front bar and said rear bar of said bottom frame each comprised of two sleeves respectively perpendicularly affixed to said side bars of said bottom frame, a connecting tube, said connecting tube having two distal ends respectively inserted into said sleeves, and two locking devices adapted to lock the two distal ends of said connecting tube to said sleeves.