Foldable frame member for a foldable bicycle

A foldable frame member for a foldable bicycle, said foldable frame member including first and second shafts connected pivotally at one end and a locking unit for retaining releasably said first and second shafts in a coaxial position, said locking unit comprising a first locking arm having a first end connected pivotally to said one end of said second shaft and a second end, and a second locking arm having a first end connected pivotally to said second end of said first locking arm and a second end connected pivotally to said one end of said first shaft, wherein:

• said first locking arm is formed as an elongated member that is generally U-shaped in cross section, said first locking arm including a base plate and two side plates which extend from said base plate, said side plates being formed with aligned longitudinally extending slots at said second end of said first locking arm;
• said second locking arm is formed as an elongated member that is generally U-shaped in cross section, said second locking arm including a base plate and two side plates which extend from said base plate, said side plates being formed with aligned pivot holes at said first end of said second locking arm, said second locking arm being shorter and narrower than said first looking arm so that said second locking arm can be received in said first locking arm when said first locking arm is pivoted toward said first shaft to retain releasably said first and second shafts in the coaxial position;
• and
• said locking unit further comprises a retaining pin extending through said pivot holes in said side plates of said second locking arm and into said slots in said side plates of said first locking arm to mount pivotally said first end of said second locking arm to said second end of said first locking arm;
• and limit means associated with said retaining pin for limiting adjustably position of said retaining pin in said slots in said side plates of said first locking arm when said second locking arm is received in said first locking arm to adjust force for retaining releasably said first and second shafts in the coaxial position.