Device for dispensing a product with improved triggering

Device for dispensing a liquid or pasty product to be dispensed comprising:

• a connection member intended to be installed at an open end of a container enclosing the product to be dispensed,
• a piston fixedly arranged with respect to the connection member,
• a cylinder body in which the piston is arranged in such a way as to define a dosing chamber between the piston and the cylinder body, the piston comprising at least one upstream opening forming a dosing inlet of the dosing chamber, and the dosing chamber comprising a dosing outlet, the cylinder body being slidable along the piston between a deployed position and a retracted position,
• an inflow non-return valve mounted on the piston and comprising an inflow membrane having a concave shape,
• the piston comprising a first part and a second part forming a sealing member fitted or over-molded around at least one portion of the first part, with this sealing member reinforcing the seal between the piston and the side wall or walls of the cylinder body, the piston and the inflow non-return valve forming separate parts and being arranged in such a way:
• wherein, when the cylinder body is immobile or is displaced towards the retracted position, the inflow membrane is tightly clamped to the top of said joint and closes the dosing inlet, and
• wherein the concave shape of the inflow membrane is elastically deformed and opens the dosing inlet when it is subjected to a negative pressure generated in the dosing chamber during the displacement of the cylinder body towards its deployed position.