Abstract: A cutter apparatus comprising an on-the-sleigh robot, a motor having a vertical output shaft and capable of shifting vertically, a rotary cutter detachably connected at the end of the output shaft of the motor, and a cordless TV camera installed on the robot. In particular, the rotary cutter has a disk-shaped support plate, whose side surface is abrasive, upper and lower disks parallel to each other, which are arranged in a row in axial direction to sandwich the support plate inbetween and whose exposed faces, respectively, are abrasive, a tapered reamer extending axially upward from the center of the upper disk, and a binder assembly to bind the tapered reamer, the upper and lower disks, and the support plate together and to fix the rotary cutter about an output shaft of the motor.

Abstract: An improved method for repairing a utility pipe such as underground sewer pipe to internally line the pipe with a tubular liner impregnated with a thermosetting resin, and in this method, a hot water hose having ejection holes is inserted in the tubular liner bag to eject hot water to effect hardening of the thermosetting resin and this hose is provided with numerous floats to float in the water even when the ejected water collects and floods inside the tubular liner bag; thus, efficient shooting of the hot water from the hot water hose is secured.

Abstract: A tubular liner bag is everted into a pipe to line the same, by first attaching an air hose end to the uneverted liner bag and then everting the tubular liner bag by water pressure provided into the manhole to the pipe. The head of the tubular liner bag is turned toward the pipe entrance when the head of the liner bag hits the inner wall of the pipe, and the tubular liner bag is everted into the pipe. The eversion is then stopped and the everted tubular liner bag is deformed to a J-shape with its head portion corresponding to the toe of the J-shape. Compressed air at a pressure not substantially greater than the pressure required to force the tubular liner bag to evert then exists in the toe section of the tubular liner bag but does not exist in the long-leg section.

Abstract: A method for lining a branch pipe comprising the steps of: preparing a tubular liner bag by sewing a rectangular nonwoven resin-absorbent fabric into a tubular shape with one end closed; attaching an impermeable plastic film over the external surface of this tubular liner bag; soaking the nonwoven resin-absorbent fabric with a hardenable fluid resin; everting the liner bag into the branch pipe until the eversion head of the liner bag is stopped by the inner wall of the main pipe; forcing the eversion head of the liner bag to turn downstream in the main pipe, thus allowing the the liner bag to evert entirely; hardening the hardenable fluid resin while inflating the liner bag; and removing that portion of the liner bag which protrudes into the main pipe.