twister 80 the speed can be reduced and the spiral twister will perform its twisting function and bind the steel bars please refer to fig8 which is a section view of the invention of pneumatic steel bar binding machine this view illustrates a static condition before a press 21 is depressed in which air is flowed from the air inlet channel 22 simultaneously to the air hole of the air inlet 25 airflow a at the middle section of the air valve 34 and since the air outlet 48 of the striking rod 38 and the air inlet 25 of the air valve 34 are split to prevent air from flowing to the upper oblique channel 24 and the lower oblique channel 29 in the static condition of the press 21 before it is depressed the main unit of pneumatic binding machine 10 is not in use it will simultaneously prevent the main unit of the binding machine when not in use air flowing into the cylinder chamber 50 and result in automatic ramming on the steel staple by the ramming mechanism 90 and result in danger please refer to fig9 and 10 which illustrates how air flows in the invention of pneumatic steel bar binding machine fig9 shows how air flows when the binding machine has hooked onto the spot where steel bars are to be bound and the press 21 is depressed in which when the trigger 21 is pressed upwardly air flows from the air.