| 摘要 |
PURPOSE:To improve working environment by providing a three-way valve which is changed over by handle operation to a cooling water circuit on the inlet side of a welding machine thereby discharging accumulated water by compressed air and preventing its backflow in the stage of changing tips. CONSTITUTION:While water is supplied to a welding machine, a handle 14 is forced to a water side position A, and a valve disc 18 is held pressed downward by a cam 35, whereby the valve is held open. Therefore, cooling water flows through a cooling inlet port 6 to an outlet port 8. When the handle 14 is changed to a neutral position C to exchange a tip 1, the valve disc 18 of a three-way valve 9 is returned upward by a spring 20, by which the valve is closed. When the handle 14 is shifted to an air side position B after this, the handle 14 forces the disc 27 downward via the cam 35, then compressed air flows through an air inlet port 7 to the outlet port 8, thereby discharging the accumulated water existing between the valve 9 and a check valve 13 through the valve 13 and preventing its backflow. |
