In-tube fixing assembly

An in-tube fixing assembly comprising:

• a primary tube having an outer wall, an inner space and an inner wall defining the inner space;
• a fixing member inserted partially or wholly into the inner space from an opened end of the primary tube and provided with at least one through hole at an appropriate position, the at least one through hole provided with an accommodation part extending in a direction from the at least one through hole toward the inner wall of the primary tube by a predetermined angle with respect to the inner wall;
• and
• at least one screw member, one end of which is defined as an operation end and the other end defined as an insertion end, the at least one screw member having has' a diameter which gradually decreases from the operation end to the insertion end,
• wherein the primary tube is deformed to form a recessed portion on the inner wall with a corresponding protruded portion on the outer wall after the at least one screw member is inserted through the accommodation part into the at least one through hole with the insertion end pressing and abutting the recessed portion on the inner wall and a portion of the screw member near the operation end kept inside the fixing member, and the recessed portion and the accommodation part respectively form a first engaging thread and a second engaging thread complementary to a screw thread of the at least one screw member.