Closure device with a movable flap

A closure device comprising:

• a wall having a front face and a rear face,
• an opening provided in said wall,
• a flap, said flap having a front face and a rear face which selectively adopts at least one of a closed position in which the flap blocks the opening and an open position in which the flap uncovers said opening,
• pins connected to a first edge of the flap,
• recesses in the wall adjacent the opening, said recesses (5) being disposed to receive the pins, and cooperate with the pins to hold the flap relative to the wall at least in its closed position, wherein said closure device further comprises:
• flexible arms connecting the pins to the first edge of the flap and biasing the pins towards one another, and said flexible arms being arranged to protrude from the first edge and from the rear face of said flap.