FIVE-WAY TWO-POSITION SPOOL-TYPE PNEUMATIC DIRECTIONAL VALVE MECHANISM

In the position of spool 3 shown in Fig. a, port 1, to which compressed air is supplied from the main, is connected to port 2, and port 4 to port 5, which leads to the atmosphere. At the same time, compressed air is admitted through channel 9 in spool 3 into left end space 7. The pressure acting on the left end of spool 3 shifts and holds it in the position shown in Fig. a. To switch over the valve, it is necessary to apply a mechanical force to head d of pusher 8 which exceeds that exerted by the air pressure at the left end of spool 3. When spool 3 is shifted to its left position, air from port 1 is admitted into port 4, and port 2 is connected to port 6, which leads to the atmosphere. If head d is released, pusher 8 and spool 3 return to the position shown in Fig. a. The principle of the valve is shown schematically in Figs. b and c.
$3676$SHP,FC$