| 摘要 |
PURPOSE: A drum of a roll up door for preventing drooping is provided to make the drum at the various lengths by extending the length of the drum as needed according to the width of a blind. CONSTITUTION: A drum(100) of a roll up door for preventing drooping is composed of a first rod member(110) and a second rod member(120). A rotation shaft(111) is only exposed through one end of the first rod member and a part of the blind is wound on the outer part of the first rod member. The second rod member is combined to the first rod member. A rotation shaft(121) is only exposed through the other end of the second rod member and another part of the blind is wound on the outer part of the first rod member. |
