Visual readout device

Claim 1

A DISPLAY MEMBER COMPRISING A PURE FLUID AMPLIFIER COMPRISING AT LEAST TWO FLUID OUTPUT PASSAGES, AN INTERACTION REGION, MEANS FOR ISSUING A MAIN STREAM OF FLUID THROUGH SAID INTERACTION REGION TOWARD SAID FLUID OUTLET PASSAGES, CONTROL MEANS FOR DEVELOPING A VARIABLE PRESSURE GRADIENT ACROSS SAID MAIN STREAM SO AS TO SWITCH THE MAIN STREAM OF FLUID BETWEEN SAID OUTPUT PASSAGES AS A FUNCTION OF SAID PRESSURE GRADIENT, SAID AMPLIFIER BEING SUCH THAT WHEN THE MAIN STRAM OF FLUID IS DIRECTION TO AN OUTPUT PASSAGE, THE PRESSURE IN THE OTHER OUTPUT PASSAGE IS BELOW AMBIENT PRESSURE, A DISPLAY MEMBER HAVING A DISPLAY REGION THEREIN, A FLUID FLOW CHANNEL EXENDING BETWEEN ONE OF SAID OUTPUT PASSAGES AND SAID DISPLAY LOCATION, A LIGHT-WEIGHT MEMBER LOCATED IN SAID FLUID FLOW CHANNEL FOR MOVEMENT BETWEEN A RETRACTED POSITION AND A DISPLAY POSITION ADJACENT SAID DISPLAY REGION SO THAT UPON INITIATION OF FLUID FLOW TO SAID ONE OF SAID OUTPUT PASSAGES SAID LIGHT-WEIGHT MEMBER IS MOVED FROM ITS RETRACTED TO ITS DISPLAY POSITION, AND MEANS FOR APPLYING A DISPLAY CONTROL FLUID FLOW SIGNAL TO SAID CONTROL MEANS FOR DIRECTING SAID STREAM OF FLUID TO SAID ONE OUTPUT CHANNEL.