To prevent possibility that clamping screws for a cleaning swivel and a master coupling and an extension rod are loosened in the case of the mounting and demounting of an outer rod and an inner rod in conventional devices though the outer rod and the inner rod are screwed to the cleaning swivel through the master coupling and the extension rod and a defect that as a place, where a seal collides, is easy to damage and the overall length of the cleaning swivel is long.
The ratios of the lead angles of screws 11, 12 for the master coupling 20 and the extension rod 40 clamped to the cleaning swivel to those of screws 21, 41 for the outer rod 3 and the inner rod 5 clamped to both the coupling 20 and the rod 40 are set in 0.2-0.6 respectively. A spare seal groove 61 is formed at the front end section of at least a swivel case 60. The base end section of the extension rod 40 is screwed and installed up to the axial center of a water-supply hole 13.
ENDO TETSUYA
UTO MASATAKA
