US Patent 10414447 Volume expansion assembly for pickup truck box

A truck box assembly including a sidewall, a pair of doors, and a support assembly is provided. The sidewall may define an opening to provide clearance for a wheel house. Each of the pair of doors extends from one side of the opening. The support assembly may be mounted to a truck box and support the sidewall as the sidewall moves between retracted and expanded positions. Each of the doors may be moveable between an open position and a closed position filling the opening in the expanded position. The support assembly may include a mount post secured to the truck box at a standard interface plate (SIP) bracket and a horizontal member extending from the mount post and secured to the truck box at a stake pocket hole.