A connector includes a base, a connecting part and a coupling piece. One end of the connecting part is connected to the base. The coupling piece is arranged on the other end of the connecting part, and includes a sliding channel having an open end located on a side edge of the coupling piece and an opposite closed end. A maximum linear distance of an outer periphery of the connecting part is less than that of the coupling piece. Another connector includes a base plate, two parallel side plates arranged on the base plate, a front plate connected to the two side plates and having a tapered positioning slot, and a positioning portion arranged on the base plate and adapted for reciprocal movement in a direction perpendicular to the base plate. The base plate, the two side plates and the front plate form an accommodating groove.