| 摘要 |
PURPOSE: To enable a connecting part between a supporter and a swing arm to be attached and detached easily, by providing a screw ring wherein a rotation supporting body forms a supporter, and engaging the screw rim bound to the swing arm in the screw thread thereof. CONSTITUTION: A screw ring 1 and a screw rim 2 provide an outside screw thread 3 and an inside screw thread 4, respectively, and are screwed into each other. The screw ring 1 is fixed to a ceiling by a screw and the screw rim 2 is screwed into a swing arm. The rotary motion is transferred from an electric motor to the outside of the screw rim 2 through a driving belt 5, and restricted by pins 7, 8 fixed to the screw ring 1 and the screw rim 2. In the screw ring 1, a notch 9 extending circumferentially in a ring shape is provided, and a tube ring 10 with a square outside cross section is contained. The expansion surface 12 of the tube ring 10 exposed from the notch 9 is expanded if a tube chamber receives superpressure to be pressed to a crimp surface 13 of the screw rim 2, so that it is acted as a brake. |
