Catheters

Claim 1

A CATHETER COMPRISING AN ELONGATED TUBE HAVING A TIP END PROVIDED WITH AT LEAST ONE DRAINAGE OPENING AND TWO PASSAGEWAYS EXTENDING LONGITUDINALLY THERETHROUGH, ONE PASSAGEWAY EXTENDING TO THE TIP END FOR DRAINING OFF LIQUID ENTERING SAME THROUGH SAID DRAINAGE OPENING, A DISTENSIBLE AND COLLAPSIBLE ANNULAR RETENTION COLLAR ON SAID TUBE DISPOSED ADJACENT SAID TIP END AND REARWARDLY OF SAID DRAINAGE OPENING, THE OTHER PASSAGEWAY COMMUNICATING AT ONE END WITH THE INTERIOR OF SAID RETENTIONN COLLAR AND AT THE OTHER END WITH MANS PERMANENTLY CONNECTED TO SAID TUBE FOR EFFECTING DISTENTION AND COLLAPSE OF SAID RETENTION COLLAR AS DESIRES, DUCH MEANS INCLUDING A CYLINDER-PLUNGER UNIT AND A SEALED-IN BODY OF NON-COMPRESSIBLE FLUID NORMALLY CONTAINED IN THE CYLINDER OF SAID UNIT BUT BEING MOVABLE BACK AND FORTH BETWEEN THE CYLINDER AND THE INTERIOR OF SAID RETENTION COLLAR WITH RECIPROCATION OF SAID PISTON, AND SPRING-BIASED, MANUALLY RELEASABLE, COACTING MEANS ON THE HEAD ENDS OF THE CYLINDER AND PLUNGER, RESPECTIVELY, FOR POSITIVELY LATCHING SAID PLUNGER IN ITS SUBSTANTIALLY INNERMOST POSITION WITHIN THE CYLINDER RESPONSIVE TO MOVEMENT OF THE PLUNGER TO SID POSITION, THEREBY TO MAINTAIN SAID RETENTION COLLAR DISTENDED FOR A DESIRED PERIOD OF TIME WITHOUT ATTENTION FROM THE OPERATOR.