Abstract:
The invention relates to a device which is used for the non-vented dispensing of liquid products from a container including a mobile base, an exhaust conduit and a push element which co-operates with a piston and a return spring. The invention is characterized in that the device includes a sealing and dosing bush bearing a sealing needle valve which can move in translation in a discharge channel in the bush, the needle valve being connected by means of a drive link to an axial guide rod which can slide in the exhaust conduit of the container that is connected to the channel by pressing on the bush and compressing the spring.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application is a continuation of pending International patent application PCT/FR2005/001060, filed Apr. 28, 2005, which designates the United States and claims priority from French patent application FR 0405452, filed May 19, 2004, the content of which is incorporated herein by reference. 

   FIELD OF INVENTION 
   The invention relates to an airless device for dispensing liquid products and, more particularly, cosmetic or pharmaceutical products. 
   BACKGROUND OF THE INVENTION 
   Airless dispensers of liquid products generally comprise a reservoir equipped with a mobile base, an outlet duct and an actuator that cooperates with a piston and a return spring. 
   However, there are certain watertightness problems associated with these dispensers, in particular regarding the chamber of a given volume that contains the doses of the product to be dispensed. Another problem relates to the incompatibility of certain products with metal, which forbids any contact with the return spring. 
   Moreover, the dispensing method is poorly controlled, which is detrimental to the dosing of the product, especially when dispensing small volumes (several milliliters). 
   Additionally, it is difficult to manufacture and assemble the various parts that make up the dispenser, particularly the elements that provide the watertightness, in which their fineness and position are decisive factors in the production of a reliable, efficient dispenser. 
   The present invention aims to resolve these problems in a satisfactory manner. 
   SUMMARY OF THE INVENTION 
   This aim is achieved according to the invention by means of a device characterised in that it comprises a watertight dosage bush, which supports a blocking needle that can be moved in translation inside an outlet channel arranged in said bush, which is connected by a drive link to an axial guide rod that is capable of sliding in the outlet duct of the reservoir, which communicates with said channel, by pressing on said bush and compressing said spring. 
   According to an advantageous characteristic, said needle is solidly attached laterally to a set of spring plates, the free ends of which are attached to the bush. 
   According to another characteristic, said drive link is equipped with a hinge that connects it to said needle, allowing it to fold inside said channel from an extended moulding position. 
   According to yet another characteristic, said rod is equipped with a lateral lug that cooperates with a safety catch arranged on the inner wall of the outlet duct. 
   According to a first alternative embodiment, said rod is equipped with a longitudinal flat section that allows the product to pass through it into the outlet channel. 
   According to a second alternative embodiment, said link consists of a cam with a triangular cross-section, articulated at the bottom, respectively, to the rod and to the bush and, at the top, to a bevelled edge of the needle. 
   According to another alternative embodiment, said channel is equipped with upper deformable lips that allow the snap-fitting of the needle. 
   According to another characteristic, said bush comprises a central sleeve forming a piston designed to cover the outlet duct by delimiting a dosage chamber around said rod and above said duct. 
   Said bush preferably comprises a peripheral skirt surrounding said spring and having, at the bottom, a flange that is capable of coming to a stop against the top part of the reservoir at the end of the dose. 
   Advantageously, the bush of the invention is manufactured as a single part together with the needle, the link and the rod by injection moulding. 
   It is provided for said bush to be additionally associated with a cover forming an actuator and closing off said outlet channel at the top. 
   This cover forming an actuator preferably comprises an orifice in line with the axis of said channel, and the needle in watertight blocking position rests against its inner circumference. 
   Thanks to the retractable needle, the device of the invention ensures automatic watertightness of the dispenser. 
   The watertightness is additionally reinforced and secured by the action of the spring plates. 
   As for the link and rod, they make it possible to break down the mode used for dispensing the product, which therefore takes place in two steps to allow better control of the dose. 
   Moreover, the dosage chamber is arranged outside the product reservoir and inside the return spring, being isolated from the latter by the wall of the sleeve, thereby protecting the product from all contact with the metal elements. 
   Finally, the device of the invention can be manufactured as a single part by injection moulding and ensures a high rate of product recovery. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be understood better from reading the following description, made in reference to the appended drawings, in which: 
       FIG. 1  shows a general axial cross-section view of one embodiment of the device according to the invention installed on an airless dispenser; 
       FIGS. 2A and 2B  show cross-section views of the embodiment of the invention shown in  FIG. 1 , respectively after being removed from the mould and after installing the cover, before assembly on a dispenser; 
       FIG. 3  shows the embodiment of the invention shown in the preceding figures in a view from below; 
       FIGS. 4A to 4E  show the device of the invention during the consecutive phases of dispensing the product. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The device according to the invention as shown in the figures is designed for equipping an airless dispenser of liquid products and, more particularly, of cosmetic or pharmaceutical products, shown in  FIG. 1 . 
   This product is contained in a reservoir R which is equipped, at the bottom, with a mobile base F and, at the top, with a shoulder E that contains an outlet duct C for the product. 
   The dispenser is also equipped with an actuator intended to cooperate with a piston (described below) and a return spring S. 
   The device of the invention, as shown in particular in  FIGS. 2A and 2B , comprises a watertight dosage bush  1  that supports a blocking needle  2 . As shown in  FIG. 2B , the needle  2  is designed to be inserted in an outlet channel  12 , in this case arranged in the top face of the bush  1  after folding and snap-fitting from the extended position for removal from the mould shown in  FIG. 2A , the device in this case being manufactured as a single part. 
   For this purpose, the channel  12  includes deformable lips  12   a  that stick out at the top and partially close off the channel. 
   The needle  2  can move in translation in the channel  12  by manually pushing on the bush  1  and compressing the spring S, being connected by a drive link  3  to an axial guide rod  4  that is capable of sliding in the outlet conduit C of the reservoir R when dispensing the product. 
   The drive link  3  is equipped with a hinge  32  that connects it to the needle  2  and allows it to fold. 
   This link consists of a cam  31  with a triangular cross-section articulated, at the bottom, respectively to the rod  4  and to the bush  1  and, at the top, to a bevelled edge  21  of the needle  2  via the hinge  32 . The link  3  therefore has a swivel axis with each of the adjacent elements. 
   The rod  4  is inserted so as to slide freely inside the duct C, filling the inner volume of the duct except where it has a longitudinal flat section  40  (see  FIG. 3 ), which allows the product to pass through said duct towards the channel  12 . The rod  4  is also provided with a lateral lug  41  that cooperates with a safety catch e made on the inner wall of the duct C. 
   When the bush  1  is installed on the reservoir R, the rod  4  penetrates the duct C and the lug  41  snaps into position under the catch e. 
   The duct C communicates with the channel  12  by means of a dosage chamber  10  delimited inside a central sleeve  11 , above the duct C and extending, in the bush  1 , coaxially to the rod  4 . 
   The sleeve  11  is designed such as to cover the duct C in a watertight manner, forming a piston. 
   In order to increase the watertightness of the chamber  10  forming the cylinder of the piston, the top edge of the duct C is advantageously equipped with a peripheral lip p. 
   The needle  2  is solidly attached laterally to a set of two spring plates  21   a ,  21   b  the free ends of which are fixed to the bush  1  by becoming blocked in two slots  20   a ,  20   b , after the folding of the needle (see  FIG. 2B ). The spring plates  21   a ,  21   b  participate in returning, guiding and holding the needle in the position that blocks the channel  12  (see  FIGS. 4A and 4D ). 
   The bush  1  also comprises a peripheral skirt  13  that surrounds the spring S and comprises, at the bottom, a flange  13   a  that comes to a stop, at the end of the dispensing stage, against the shoulder E of the reservoir R. 
   The flange  13   a  also cooperates with a radially projecting raised edge T made in the reservoir R which ensures that the bush  1  is held in its housing and that the spring S is kept under stress in the watertight closed position of the dispenser (see  FIG. 4E ). 
   The device of the invention additionally comprises a cover  5  forming an actuator which closes off the channel  12  in a watertight manner at the top. 
   This cover is, for example, snap-fitted (as in the alternative embodiment shown in the figures) or inserted onto the bush  1 . 
   The cover  5  comprises a lateral ejection orifice  50 , possibly associated with a nozzle, the end of the needle  2  resting against its inner circumference in the position in which it blocks the dispenser in a watertight manner. 
   When necessary, in order to increase the watertightness, the inner circumference of the orifice  50  is equipped with an angular ring forming a seat for the end of the needle  2 . 
   The operation of the device is described below in reference to  FIGS. 4A to 4E . 
   In the resting position shown in  FIG. 4A , the end of the needle  2  is resting against the orifice  50  of the cover  5 , under the simultaneous action of the spring plates  21   a ,  21   b  and the spring S, which is under slight stress, thus hermetically blocking the channel  12  and, more generally, the whole dispenser. 
   At the same time, while the sleeve  11  is pushed upwards, the rod  4  is pulled downwards into the duct C by the safety catch e, contributing to the rotation torque to which the link  3  is subjected in clockwise direction (see arrows), thus increasing the pressure on the needle  2 . 
   The position shown in  FIG. 4B  corresponds to the start of the product dispensing phase, the cover/actuator  5  beginning its descent in response to the vertical manual pressure exerted by the consumer. 
   Throughout this phase, the rod  4  remains immobile due to the inevitable friction involved in its sliding insertion in the duct C. 
   As for the sleeve  11 , it begins its descent by compressing the spring S and subjecting the link  3  to a rotation torque in anticlockwise direction. This movement drives the translation movement of the needle  2  towards the rear and its retraction from the ejection orifice  50 . 
   At the same time, the dosage chamber empties gradually by the piston effect of the sleeve  11 , the scraping of its wall by the lip p of the duct C causing the product to be dispensed through the channel  12  and the orifice  50 . 
   While the pressure is maintained, the movement continues until the link  3  comes to a stop against the bevelled edge  21  of the needle  2 , as shown in  FIG. 4B . 
   The dispenser is then fully open. 
   In the position shown in  FIG. 4C , the clamping of the rod  4  in the duct C is ended by the forces pushing on the actuator  5 . The rod  4  begins to slide towards the bottom inside the duct C, while the link remains resting against the needle  2 , thereby moving towards reaching the dosage that is finally obtained when the flange  13   a  of the skirt  13  of the bush reaches the shoulder E of the reservoir R ( FIG. 4D ). 
     FIG. 4E  shows the return to the resting position of  FIG. 4A . The release of the manual force causes the release of the spring S. This release initially causes the sleeve  11  and the actuator  5  to rise until the needle  2  comes to a stop against the orifice  50 , the rod  4  remaining immobilised in the duct C. 
   The link  3  swivels in clockwise direction and pushes the needle  2  back against the orifice  50 . This movement causes the suction of the product in the reservoir R and the gradual filling of the chamber  10  inside the sleeve  11 . 
   Then, the clamping of the rod  4  in the duct ends and the rod  4  rises back up until its lug  41  comes to a stop against the catch e of the duct C, the needle being held in its forward position by the action of the spring plates  21   a ,  21   b.    
   The spring S is then held under slight stress due to the flange  13   a  having come to an anticipated stop against the projecting raised edge T of the reservoir R.