The utility model relates to a connecting device technical field of case and bag especially discloses an improvement formula is pulled and is detained and clip, including the body, the body has the first side wall, connects in second lateral wall, the third lateral wall of the relative both sides of the first side wall respectively, and second lateral wall and third lateral wall be parallel arrangement each other, and the first side wall is provided with the recess, and the second lateral wall is equipped with the opening with the recess intercommunication, and the third lateral wall is equipped with the through -hole that link up the body, during the in -service use, need to pull to detain and install on the coupler body to pull detain and the coupler body between install the spring, the utility model discloses a set up recess and opening pulling to buckle, during the equipment can with the spring in the recess is installed to the opening, then will pull on the knot assembles the coupler body together with the spring together the product of the being convenient for equipment operation of automizing to improve the production efficiency of product greatly.