Support Mechanism and Support Assembly for Soft Top of Truck Bed

The provided are a support mechanism and support assembly for a soft top of a truck bed. The support mechanism includes a side rail, a first folding assembly, and a second folding assembly, where the side rail is fixed to the truck bed; the first folding assembly includes a first main support frame that is rotatably provided on the side rail; a bottom end of the first main support frame is connected to a movable component; the movable component is rotatably connected to the side rail, such that the bottom end of the first main support frame is adjustable at least along a length direction of the side rail; the second folding assembly includes a second main support frame; the second main support frame is rotatably provided on the side rail; and the second folding assembly is foldable and storable above the first folding assembly.