Electromagnetic valve with actuation-indicating means

An electromagnetic valve with an apparatus for indicating mechanical actuation. The valve comprises (a) a valve seat defining a cavity communicating with an inlet and an outlet, (b) a sleeve partially fitting in the cavity and having a passage communicating with a chamber communicating with the inlet and the outlet, (c) a piston being slidable within the chamber between a first position closing the inlet and the outlet and a second position opening the inlet and the outlet, (d) a spring being sited within the chamber, for biasing the piston to the first position, (e) a solenoid enclosing the sleeve, for attracting the piston to the second position when activated, (f) a rod comprising a first end attached to the piston and a second end extending throughout the sleeve, (g) a photocoupler being mounted on the sleeve and comprising a transmitter and a receiver and (h) a leaf being mounted on the sleeve and comprising a tip bearing a shield having a first position restraining light emitted by means of the transmitter from reaching the receiver and a second position permitting light emitted by means of the transmitter to reach the receiver. The shield is retained in its first position when the piston is in its first position and is in its second position when the second end of the rod pushes the leave upward when the piston is in its second position.