Plastic dispenser for liquids or other substances

A dispenser for dispensing liquid substances or substances in the form of cream or paste including a plurality of components, comprising

• a bottle for containing the substance to be dispensed and having an interior and a mouth,
• a manual pump for dispensing a predetermined quantity of substance, and
• a socket ring for fixing the pump to the bottle mouth,
• the pump comprising:
• a substantially cylindrical hollow body having first and second open ends, said body having an interior,
• a flexible non-return valve arranged at said first end,
• a substantially cylindrical hollow shaft having an interior, said shaft situated substantially coaxial to the hollow body and partly enclosed within said bottle interior, one end of said shaft projecting out of said bottle interior through the second end of the hollow body, the shaft being movable axially in both directions relative to the hollow body, the projecting end of the shaft carrying a plastics dispensing knob provided with a dispensing nozzle which communicates with the interior of the shaft, the other end of the shaft comprising at least one aperture for communication between the interior of the shaft and the interior of the hollow body, a piston unit comprising a piston movable in both directions under fluid-tight conditions within the hollow body, a portion of the interior of the hollow body situated between the piston and the non-return valve defining a pressure chamber, the piston being mounted on the shaft and being movable in both directions relative to the shaft to open or close said at least one aperture in the shaft;
• first return means for returning the piston to a rest position in which said at least one aperture in the shaft is closed;
• second return means for returning the shaft into the position in which it projects from the hollow body when pressure on the dispensing knob ceases;
• an annular closure element for the second end of the hollow body, said closure element constituting a guide for the shaft;
• and
• connection means provided within the pump for connecting the interior of the bottle to the atmosphere, said connection means being interrupted when the piston is in its rest position;
• said first return means including a shank comprising a skirt which deforms elastically when the dispensing knob is pressed,
• said second return means being made of an elastically deformable material, said second return means comprising an annular bellows element formed with the dispensing knob,
• all of said components of the dispenser being formed from a plastic material, which is of a type which enables both substantially rigid components and substantially elastic components to be formed.