An overload protection mechanism includes a frame and a positioning assembly received in the frame. The frame includes at least one side plate, the at least one side plate defining a receiving depression. The positioning assembly includes a fixing sleeve, at least one elastic member received in the fixing sleeve, and at least one latching member positioned on the at least one elastic member and movably received in the receiving depression. The at least one side plate further defines a slanted repositioning surface adjoining the receiving depression. The positioning assembly is slidable relative to the frame with the at least one elastic member resisting the at least one latching member to press the at least one latching member along the slanted repositioning surface until the at least one latching member is received in the receiving depression.