US Patent 9879811 Quick-fit hydraulic or hydrodynamic coupling for pressurized fluids

The quick-fit coupling (1) for pressurized fluid comprises a valve body (3) extending along a longitudinal axis (L) and having an axial cavity (4) wherein a shutter stem (5) is axially movable with respect to the valve body in contrast to and by action of at least one elastic element (6) between a position for opening and a position for closing an axial passage of fluid through said cavity (4), the stem (5) being configured so as to be subjected by the fluid present in the cavity (4) to a resultant force having a substantially null component at least in an axial direction.