Liquid dispenser device

1. A liquid dispenser device for being associated with a liquid reservoir (R), said device comprising:

a liquid dispenser orifice ( 25 ); and

a pusher ( 2 ) that is axially displaceable down and up between a rest position and a depressed position;

a chamber ( 10 ) provided with an inlet valve ( 5 , 15 ), an outlet valve ( 27 , 32 ), and a piston ( 3 ) that is suitable for varying the volume of the chamber ( 10 ), the outlet valve comprising a movable valve member ( 32 ) and a valve seat ( 27 ), the valve member being secured in displacement with the piston ( 3 ), the piston ( 3 ) including an elastically-deformable portion ( 31 ) that is deformed by the pusher ( 2 ) in its depressed position, in such a manner as to open the outlet valve, the pusher ( 2 ) forming the valve seat ( 27 ) of the outlet valve;

the dispenser device being characterized in that it further comprises a body ( 1 ) for being mounted on an opening (C) of a reservoir (R), the body ( 1 ) forming a piston-receiving slide-cylinder ( 17 ) defining a free top edge ( 171 ), the piston ( 3 ) including a piston lip ( 36 ) in leaktight sliding contact in the piston-receiving cylinder ( 17 ), and an annular flange ( 31 ) that extends outwards above the top edge ( 171 ) of the cylinder ( 17 ), the valve member ( 32 ) being formed on the outer periphery of the annular flange ( 31 ), the elastically-deformable portion being formed by the annular flange ( 31 ), the pusher ( 2 ) coming to bear against the annular flange ( 31 ) when the flange is in abutment against the top edge ( 171 ) of the cylinder, thereby deforming the flange and opening the outlet valve.

2. A dispenser device according to claim 1 , in which the piston ( 3 ) is a differential piston that is suitable for being displaced by the variations in the pressure of the liquid in the chamber, the piston being momentarily out of contact with the pusher.

3. A dispenser device according to claim 1 , in which, when the pressure in the chamber is less than a predetermined threshold, the piston ( 3 ) is in contact with the pusher ( 2 ) by means of a return spring ( 4 ) that urges the piston ( 3 ) towards the pusher ( 2 ).

4. A dispenser device according to claim 1 , in which the pusher ( 2 ) defines a portion of the chamber ( 10 ).

5. A dispenser device according to claim 1 , in which the pusher ( 2 ) comprises a top plate ( 21 ) on which a user can exert pressure by means of a finger, and a peripheral skirt ( 22 ) forming the dispenser orifice ( 25 ), the plate ( 21 ) forming the outlet valve seat ( 27 ) and an annular bearing rim ( 26 ) for coming to bear against the flange ( 31 ) so as to deform it, the rim ( 26 ) being situated radially outside the top edge ( 171 ) of the cylinder ( 17 ).

6. A dispenser device according to claim 5 , in which the piston ( 3 ) includes a flexible membrane ( 33 ), and an anchor collar ( 34 ) that is engaged with the pusher ( 2 ), the membrane ( 33 ) connecting the valve member ( 32 ) to the collar ( 34 ), defining an outlet channel ( 28 ) for the liquid as far as the dispenser orifice ( 25 ).

7. A dispenser device according to claim 1 , in which the deformable portion ( 31 ) presents resistance to deformation that is greater than the force exerted by the spring, and greater than or equal to the maximum pressure existing in the chamber.

8. A dispenser device according to claim 1 , in which the deformable portion ( 31 ) of the piston deforms after the pusher has reached its depressed position.