Compressed air, supplied from the main to port 1, is admitted into port 2 (Fig. a). When palm button d of pusher 6 is pressed, spool 4 is shifted to the left and connects port 2 to port 3, which leads to the atmosphere. When palm button d of pusher 6 is released, spool 4 is returned by spring 5 to its initial position. The principle of the valve is shown schematically in Figs. b and c.
$3693$SHP,FC$