A conveyor chain assembly including a multiplicity of rows of chain modules, each module includes a plurality of link ends with coaxially aligned openings. A chain pin passes through the coaxially aligned openings of adjacent modules. On the opposite ends of each module is a plug socket which is adapted to house a plug. The plug includes a shaft and an arm. The arm is moveable when the shaft is mounted in the socket between a first position in which the arm restricts axial movement of the chain pin and a second position in which the arm does not restrict axial movement of the chain pin.