the container 20 from the inside thereof to block tightly against the container 20 and continuously fix the socket 23 and the container 20 via the fixing element 25 so that the assembling processes can be finished moreover for more effective and easily assembling the socket the present invention can further include a set of fixing devices separately set on the socket 23 and the container 20 with this set of fixing devices the fixing element 25 as shown in fig3 will not be needed any more and the operator only need to process a translation or a rotation and the socket 23 can be fixed on the container 20 as shown in fig4 which illustrates the assembling and structural schematic view in the second embodiment according to the present invention a female thread is set at an inner surface of a surrounding structure 320 of an opening 301 on a container 30 and a male screw is set on a connecting section 330 of a socket 33 the surrounding structure 320 and the connecting section 330 are the fixing devices which can mutually integrate to each other in this situation the assembling steps are as described above electrically connecting a circuit board not shown please refer to fig3 to the socket 33.