Piston-stopper dispenser

Abstract

A dispenser for a liquid cosmetic product, includes a reservoir, an internal piston, and an applicator end piece provided with and end valve. The dispenser is characterised in that the reservoir is defined inside the end piece, at a first end, by the valve, and, at the other end, by the piston, the piston forming a stopper screwed onto a threaded axial rod fixed to a base which is rotatably connected to the end piece.

1 . A dispenser for liquid cosmetic products comprising a reservoir, an internal piston and an applicator nozzle provided with an end valve, characterised in that said reservoir is delimited inside the nozzle, at a first end, by said valve and, at the other end, by said piston forming a plug, which is screwed onto a threaded axial rod formed integral with a base rotatingly connected to said nozzle.  
   
   
       2 . A dispenser according to  claim 1 , characterised in that said piston comprises, on the one hand, a cylindrical compression element covering said threaded rod and which has a peripheral lip in watertight contact with the inside wall of the reservoir and, on the other hand, on the outside of said reservoir, a connecting collar attached to said rod and rotatingly blocked in said base.  
   
   
       3 . A dispenser according to  claim 1 , characterised in that said reservoir is provided with a jacket fixed in the nozzle which is extended, as required, by a sleeve housed in the base.  
   
   
       4 . A dispenser according to  claim 3 , characterised in that said sleeve is provided with means for blocking the rotation of said piston and means for axial locking in the base.  
   
   
       5 . A method for packaging a liquid cosmetic product in a dispenser of the type that comprises an applicator nozzle, enclosing an internal piston and a reservoir blocked at a first end by a valve, characterised in that the reservoir is filled by its other end, with the dispenser in its inverted position, and then the piston is inserted in the form of a plug, expelling the air contained in the reservoir in order to close off this other end in a watertight manner, and said piston is locked in this closed position.  
   
   
       6 . A method according to  claim 5 , characterised in that, prior to closing the reservoir, an axial rod formed integral with a base is inserted and fixed in said piston.  
   
   
       7 . A method according to  claim 6 , characterised in that the fixing of the rod in the piston and the transmission of the movement are provided by elastic distortion of the material from which the piston is made.  
   
   
       8 . A method according to  claim 5 , characterised in that the piston is locked in the closed position of the reservoir by axially and rotatingly connecting the base to the nozzle.  
   
   
       9 . A method according to  claim 5 , characterised in that said piston is rotatingly blocked by cooperation with limit stops formed integral with the nozzle.  
   
   
       10 . A method according to  claim 5 , characterised in that the watertightness of the reservoir is only ensured during the step in which said piston is locked.  
   
   
       11 . A method according to  claim 5 , characterised in that the reservoir is filled leaving a small amount of air inside it forming a buffer in order to avoid any leaks from the valve when inserting the piston.