PURPOSE: To avoid the influence of residual pressure by carrying out retreating motion of a nozzle for washing by both of a return spring and washing water pressure by way of temporarily supplying wash water to a disc valve at the time of stopping washing.
CONSTITUTION: In the case of using a nozzle for washing at a retreated position for washing, by communicating a passage corresponding to an opening of a base end side cylinder chamber on a fixed disc 52 of a disc valve 4 to a water supply source through a communicating passage of a revolving disc 51, wash water is delivered and supplied to the base end side cylinder chamber and the nozzle for washing is made to advance forward. At the time of delivering and supplying wash water temporarily to the disc valve 4 in the case of retreating motion of the nozzle for washing at the time of stopping washing, a passage corresponding with an opening of a head end side cylinder chamber is simultaneously returned to an initial state communicated to the water supply source, and wash water is delivered and supplied to the head end side cylinder chamber. Consequently, the nozzle for washing is retreated by both of a return spring and pressure of wash water delivered and supplied to the head end side cylinder chamber.
FURUKAWA HIDEKI
MATSUBARA OSAMU
SAWAKI ATSUSHI
KAWAI SHINJI
