Cap for safely filling and closing an engine oil tank, in particular of an aircraft engine

1. A cap ( 4 ) for safely filling and closing an engine oil tank ( 1 ), the cap ( 4 ) comprising an elongated tubular oil feed body ( 6 ) having a first end portion ( 8 ) fitted in a fluidtight manner to an inlet ( 3 ) of an engine oil tank ( 1 ); a removable cover body ( 25 ) for closing said first end portion ( 8 ); an oil feed valve ( 23 ) fitted to the tubular body ( 6 ) and movable between an open position, allowing oil flow into the tank, and a closed position, preventing oil outflow from the tank; and a dipstick ( 26 ) for measuring the oil level in the tank, and which is housed in said tubular body ( 6 ) and carried by said removable cover body ( 25 ); wherein said feed valve is located close to said first end portion, said cap also comprising a monostable valve ( 27 ) controlled by said dipstick ( 26 ),

wherein

said feed valve comprises a lateral opening ( 13 ) formed through said tubular body, said opening ( 13 ) extending in such a position as to have a passage portion unaffected by the oil and located above the maximum oil level ( 21 ) in the tank,

said feed valve further comprises a movable flap ( 15 ) closing said opening,

said movable flap is hinged to said tubular body to rotate about a hinge axis ( 18 ) perpendicular to an axis ( 7 ) of said tubular body, and

said hinge axis extends above the oil level in said tank.

2. A cap as claimed in claim 1 , wherein said feed valve and said monostable valve are separate and spaced apart along said tubular body ( 6 ).

3. A cap as claimed in claim 1 , wherein said tubular body comprises a second end portion ( 10 ) opposite said first end portion and communicating with the inside of the tank, said monostable valve being carried by said second end portion.

4. A cap as claimed in claim 3 , wherein said monostable valve ( 27 ) is housed inside said second end portion ( 10 ) of said tubular body.

5. A cap as claimed in claim 4 , wherein said monostable valve comprises a shutter ( 28 ) movable axially inside said second end portion; and an elastic thrust member ( 30 ) for holding said shutter in a closed position preventing oil outflow from the tank; said dipstick exerting pressure, in opposition to that exerted by the elastic member, to hold the shutter in a rest position connecting the inside of the tubular body to said tank.

6. A cap as claimed in claim 5 , wherein the shutter is a hollow shutter; and, in said rest position, the elastic member ( 30 ) is housed completely inside said shutter.

7. A cap as claimed in claim 5 , wherein said second end portion has a number of radial passages ( 12 ) connecting the tank to the inside of the tubular body; said passages being formed along the portion traveled by said shutter when moving between said rest position and said closed position.

8. A cap as claimed in claim 1 , wherein, when fitted to said tank, said hinge axis extends parallel to the maximum oil level in the tank.

9. A cap as claimed in claim 1 , wherein said movable flap is located on the outside of said tubular body.

10. A cap as claimed in claim 1 , further comprising a filtering member ( 32 ) located inside said tubular body ( 6 ), upstream from said feed valve in the oil flow direction into the tank.