Operations of the clutch and the brake are roughly as follows.
When compressed air is sent to the clutch cylinder block in the
transmission, the moved piston shifts the clutch plate and the brake
plate holding the friction plate from both sides to disengage the brake
and engage the clutch. When the clutch brake solenoid valve is turned
off, compressed air is discharged and the piston is returned to the
original position by spring force. This returning piston disengages the
clutch and simultaneously applies the brake.