A coupling mechanism includes a pair of bracket and a spacer plate sandwiched in between the pair of brackets. Each bracket of the of brackets comprise a first cutout formed on a top face of each bracket of the brackets. A retainer bar coupled to the pair of brackets, wherein the retainer bar comprises a second cutout formed on a bottom face of the retainer bar and a flat top surface. The second cutout and the first cutout abut each other to form an opening, wherein the opening receives an axle of a conveyor roller.