Indicating means for fluid filters

Claim 1

IN COMBINATION WITH A FLUID PRESSURE DEVICE INCLUDING A HOUSING CONTAINING A CHAMBER, AN INLET, AND AN OUTLET, AND A FIRST MEMBER MOUNTED FOR MOVEMENT IN SAID CHAMBER, INDICATING MEANS FOR INDICATING THE POSITION OF SAID MEMBER IN SAID CHAMBER COMPRISING A SHAFT MOUNTED FOR ROTATION IN A THROUGH BORE IN SAID HOUSING; AN ACTUATING MEMBER IN SAID CHAMBER SECURED TO SAID SHAFT, SAD ACTUATING MEMBER BEING ARRANGED FOR ENGAGEMENT BY SAID FIRST MEMBER TO ROTATE SAID SHAFT UPON MOVEMENT OF SAID FIRST MEMBER; AN INDICATING ELEMENT CONTAINING A THROUGH OPENING, SAID INDICATING ELEMENT BEING EXTERNAL OF AND ADJACENT SAID HOUSING, A FIRST PORTION OF SAID SHAFT HAV-ING A SMOOTH CYLINDRICAL SURFACE EXTENDING THROUGH THE OPENING IN SAID INDICATING ELEMENT, SAID INDICATING ELEMENT CONTAINING ALSO A THROUGH-SLOT EXTENDING IN A DIRECTION NORMAL TO SAID SHAFT, SAID SLOT EXTENDNG FROM A FIRST POINT ON THE PERIPHERAL SURFACE OF SAID INDICATING ELEMENT TO A SECOND POINT SPACED FROM AND ON THE OPPOSITE SIDE OF SAID SHAFT FROM THE FIRST POINT, THEREBY DEFINING A PAIR OF LEG PORTIONS ON SAID INDICATING ELEMENT; MEANS ON THE OPPOSITE SIDE OF SAID SHAFT FROM SAID SECOND POINT FOR CLAMPING TOGETHER THE LEGS OF SAID INDICATING ELEMENT TO RIGIDLY CONNECT SAID INDICATING ELEMENT WITH SAID SHAFT; SAID HOUSING CONTAINING AT OPPOSITE ENDS OF THE BORE THEREIN A PAIR OF COUNTERBORED RECESSES; A PAIR OF O-RING SEALS MOUNTED, RESPECTIVELY, IN SAID HOUSING RECESSES, SAID O-RING SEALS NORMALLY HAVING SURFACE PORTIONS WHICH EXTEND SLIGHTLY BEYOND THE ADJACENT SURFACES OF SAID HOUSING; SAID SHAFT HAVING A THREADED SECOND PORTION EXTENDED AT ONE END ON THE OPPOSITE SIDE OF SAID INDICATING ELEMENT FROM SAID HOUSING; AND MEANS COOPERATING WITH SAID THREADED SECOND SHAFT PORTION FOR DRAWING SAID INDICATING ELEMENT AND SAID ACTUATING MEMBER TOWARD EACH OTHER AND SAID HOUSING TO THEREBY COMPRESS SAID O-RING SEALS.