| 摘要 |
PURPOSE:To easily perform the installation and removal of sheathing from ground by a method in which an air bag is set in an open trench and compressed air is charged into the air bag for expansion. CONSTITUTION:A shrink air bag 11 is set in an open trench 1, an air hose 13 is connected to an air source, and then air is charged into the air bag 11. By this, the air bag 11 is expanded under the condition that a space 14 to house cable, etc., is secured between its lower part and the bottom of the open trench 1, whereby both side walls of the open trench 1 are supported to play the role of a sheathing device. After air is charged, a cap is covered on a coupler 12 or the valve of the air hose is closed. When removing the sheathing device, the cap is removed or the valve is opened to release the air, and the air bag 11 is shrunk and taken out. |
