PURPOSE: To eliminate the occurrence of uneven spraying by securing cam rods for opening and closing to the revolving shafts of the on-off valves of the water feed pipes of the injection ports disposed to a moving boom, and disposing operating rods for valve opening and closing opposedly to the cam rods to a moving boom supporting frame.
CONSTITUTION: In a telescopic spraying device which freely slidably supports a moving boom 3 to the supporting frame 2 of a telescopic boom 1, on-off valves 8 are provided to the water feed pipes 7 of the injection ports 6 disposed to the moving boom 3, and valve opening cam rods 10 and closing cam rods 11 are secured to the revolving shafts 9 of the on-off valves 8. Said valve opening operating rods 12 and closing operating rods 14 are provided to the supporting frame 2 of the moving boom 3 opposedly to said cam rods 10, 11 respectively, whereby the device is constituted. When the moving boom 3 is extended, the opening operating rods 12 operate and the injection ports 6 start spraying work (at this time, the closing rods 14 turn freely and do not operate). To contract the moving boom 3, the operations become opposite from the above, and the closing operating rods 14 act to the closing cam rods 11, thereby closing the valves 8.
