A link assembly comprising a shaft provided with a positioning surface that includes threads, an arm coupler including an interfacing assembly and a pair of grommet contacting members, wherein the interfacing assembly includes an interfacing member that receives the positioning surface and inner and outer grommets that are provided with inner surfaces that receive the interfacing member, and the pair of grommet contacting members includes an inner grommet contacting member that receives the positioning surface shaft and contacts the inner grommet and an outer grommet contacting member that receives the positioning surface and contacts the outer grommet.