AUTOMATIC PRESSURIZED FLUID SWITCHING DEVICE

摘要

This invention relates to a device for automatically switching discharge of pressurized fluid from outlet ports. To be more specific, this invention relates to an automatic pressurized fluid switching device for performing a switching operation using the pressure of pressurized fluid in itself without using electrical elements. An object of the invention is to provide an automatic pressurized fluid switching device having an excellent switching performance without using an electrical element so as not to be complicated in structure. To attain the object according to the invention, there is provided an automatic pressurized fluid switching device comprising an inlet port for introducing pressurized fluid, a plurality of outlet ports for discharging the pressurized fluid, a switching valve disposed between the inlet port and the outlet ports for switching over the outlet ports, a pilot valve for piloting the switching operation of the switching valve, and a reaction member for controlling the pilot action of the pilot valve in response to the pressure of the pressurized fluid introduced, which is characterized in that the pilot valve is provided with a first pilot unit in which the pilot action of the pilot valve is controlled only by the reaction member, and a second pilot unit in which the pilot action of the pilot valve is controlled by the reaction member in its initial and final stages and directly by the pressurized fluid in its middle stage. According to the invention, two lineages of the pilot action of the pilot valve for piloting the switching action of the switching valve can be constituted. The lineages are formed of the pilot action controlled only by the reaction member in the first pilot unit and the pilot action controlled by both of the reaction member and the fluid in the second pilot unit. The pilot action in the second pilot unit is controlled by the reaction member in the initial and final stages and by the pressurized fluid in the middle stage. Consequently, the pilot action in the second pilot unit in the middle stage can be securely effected even when the pressurized fluid introduced thereinto is little at the time of being again operated after stopping at the intermediate point of the switching action. Thus, smooth switching action can be performed securely.