Patent ID: 8936269
Filing Date: 2015-01-20
Classification: B62K

Abstract:
1. A retractable frame structure for a tandem trailer, comprising a front frame, a rear frame, a bottom frame, two wheel brackets respectively bilaterally mounted at said bottom frame near a rear side thereof for supporting a respective wheel, and a trailer bar pivotally connected to one lateral side of said bottom frame near a front side thereof for coupling to a bicycle, wherein: said front frame has respective bottom ends of two side bars thereof respectively pivotally connected to two distal ends of a front side of said bottom frame by a respective pivot member, and a top side thereof pivotally connected to said rear frame; said rear frame has respective bottom ends of two side bars thereof respectively pivotally connected to two distal ends of a rear side of said bottom frame by a respective pivot member, and a top side thereof pivotally connected to the top side of said front frame; said bottom frame is a substantially rectangular open frame retractable longitudinally back and forth between an extended position defining a relatively greater accommodation space for two-seat seating arrangement in a fore-to-aft manner and a retracted position defining a relatively smaller accommodation space for one-seat seating arrangement, wherein said front frame comprises at least one coupling portion located on the top side thereof; said rear frame comprises at least one coupling portion located on the to side thereof and respectively detachably connected to the at least one coupling portion of the front frame, wherein said at least one coupling portion of said front frame comprises two opposite sidewalls and a through hole located on each said sidewall; said at least one coupling portion of said rear frame comprises an axial hole, at least one transverse through hole extending across said axial hole, and an elastic positioning pin mounted in said axial hole, said elastic positioning pin having one end thereof positioned in one side inside the respective coupling portion of said rear frame and an opposite end thereof provided with a retaining rod that is inserted through one transverse through hole of the respective coupling portion of said rear frame and engaged into the through hole on one sidewall of the respective coupling portion of said front frame.