Abstract:
A fluid dispenser member designed to be associated with a fluid reservoir ( 50 ) and comprising: 
       a chamber ( 1 ) in which the fluid is put under pressure, the chamber being provided with an inlet valve ( 161, 38 ) and with an outlet;    a dispensing orifice ( 25 );    a main piston ( 133 ) in leaktight sliding contact inside a main cylinder ( 242 ) for the purpose of causing the volume of the chamber to vary;    a pusher ( 20 ) that can be actuated to generate relative movement between the main piston and the main cylinder; and    a differential piston ( 31, 32, 33 ) in leaktight sliding contact inside the pusher for the purpose of selectively unmasking the outlet of the chamber;    said dispenser member being characterized in that it further comprises stroke-limiting means ( 28, 39 ) for limiting the stroke of the differential piston in the pusher, said stroke-limiting means being provided between the pusher and the differential piston.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0007]     This application claims the benefit under 35 U.S.C. §119(e) of pending U.S. provisional patent application Ser. No. 60/561,511, filed Apr. 13, 2004, and priority under 35 U.S.C. §119(a)-(d) of French patent application No. FR-03.15192, filed Dec. 22, 2003. 
     
    
     TECHNICAL FIELD  
       [0008]     The present invention relates to a fluid dispenser member that is generally designed to be associated with a fluid reservoir so as to constitute therewith a fluid dispenser. It is a dispenser member that is generally actuated manually by means of a user&#39;s finger. The fluid is dispensed in the form of a sprayed stream of fine droplets, a continuous trickle, or a dollop of fluid, in particular for viscous fluids, such as cosmetic creams. Such a fluid dispenser member can, in particular, be used in the fields of perfumes, cosmetics, or indeed pharmaceuticals, for dispensing fluids of various viscosities.  
         [0009]     The present invention relates more particularly but not exclusively to a type of dispenser member that can be referred to as a “pusher-pump”. That name can be explained by the fact that the dispenser member comprises a pusher that not only forms a dispensing orifice but also defines a portion of a fluid chamber inside which fluid is selectively put under pressure. When the dispenser member is a pump, that chamber is a pump chamber. A particularity of such a pusher-pump lies in the fact that an inside surface of the pusher, which surface is substantially cylindrical in general shape, serves as a leaktight slide cylinder for a piston that moves in leaktight contact inside said cylinder, thereby selectively unmasking the dispensing orifice. In general, the piston is a piston of the differential type which moves in response to variation in the pressure of the fluid inside the chamber. The differential piston should be distinguished from the main piston which is caused to move by actuating the pusher. Thus, such a pusher-pump includes a differential piston and a main piston, which pistons can move in leaktight contact in respective cylinders. The main cylinder for the main piston can also be formed by the pusher.  
       BACKGROUND OF THE INVENTION  
       [0010]     That applies in particular in the pump described in Document WO 97/23304. The pusher has a push wall on which pressure is exerted by means of a finger for the purpose of actuating the pusher. In addition, the pusher has a skirt that extends downwards from the push wall. Said skirt forms a first leaktight slide cylinder for a differential piston and a main second cylinder for the main piston of the pump. The differential piston is dissociated from the main piston. The differential piston is urged away from the push wall by a spring that serves both as a return spring and as a precompression spring. The slide cylinder for the differential piston is provided with an outlet duct that leads to a nozzle received in a recess formed in the skirt of the pusher. The nozzle forms a dispensing orifice via which the fluid is discharged from the dispenser member. In addition, the recess formed by the skirt is provided with a swirl system which co-operates with the nozzle to entrain the fluid in a swirling movement before it is discharged through the dispensing orifice. The swirl system is conventionally made up of one or more tangential swirl channels opening out into a swirl chamber accurately centered on the dispensing orifice. The swirl system is in the form of a network recessed into the recess in the skirt. The recessed network is then associated with the separate nozzle that comes to isolate the swirl channels and the chamber. Thus, the slide cylinder of the differential piston is in the form of a cylindrical surface interrupted only at the outlet channel. When the pusher is pressed, the main piston rises up inside the main cylinder of the pusher, thereby causing the differential piston to move by sliding in leaktight manner inside the differential cylinder. That causes the spring to be compressed: the differential piston then moves upwards towards the push wall of the pusher. The active sealing lip of the differential piston, which lip is directly in contact with the fluid, slides in the bottom portion of the cylinder that is situated below the outlet channel. As soon as the differential piston reaches the outlet duct, the fluid put under pressure in the chamber is delivered from the chamber through said duct and reaches the nozzle, where it is swirled and discharged through the dispensing orifice.  
         [0011]     The pump of Document WO 97/23304 is made up of five essential component elements, namely a body designed to be associated with a fluid reservoir, the pusher, a ball forming an inlet valve member, the differential piston, and the nozzle. The body forms the main piston.  
         [0012]     In the prior-art document, the differential piston is pushed by the return and precompression spring against the body which thus forms a rest abutment for the differential piston. When the pressure rises in the chamber, the differential piston leaves its abutment contact on the body and moves upwards towards the dispensing wall so as to uncover the outlet duct which leads to the nozzle. Consequently, the rest position of the differential piston is directly dependent on the body.  
       SUMMARY OF THE INVENTION  
       [0013]     An object of the present invention is to define a dispenser member in which the displacement of the differential piston is completely independent from the body.  
         [0014]     To achieve this object, the present invention proposes a fluid dispenser member designed to be associated with a fluid reservoir and comprising: a chamber in which the fluid is put under pressure, the chamber being provided with an inlet valve and with an outlet; a dispensing orifice; a main piston in leaktight sliding contact inside a main cylinder for the purpose of causing the volume of the chamber to vary; a pusher that can be actuated to generate relative movement between the main piston and the main cylinder; and a differential piston in leaktight sliding contact inside the pusher for the purpose of selectively unmasking the outlet of the chamber; said dispenser member being characterized in that it further comprises stroke-limiting means for limiting the stroke of the differential piston in the pusher, said stroke-limiting means being provided between the pusher and the differential piston. Thus, the differential piston is connected to the pusher in such a manner that its displacement is solely dependent on its interaction with the pusher, and no longer with the body. In this way, the pusher and the differential piston together constitute an independent entity which can be mounted on the body in a single operation. In the above-mentioned prior-art document, the differential piston does not really dependent on the pusher or on the body, so assembling the pump is relatively complicated. With a differential piston contained within the pusher, assembling the dispenser member is much simpler.  
         [0015]     In an advantageous embodiment, the pusher comprises a push wall that can be pressed to actuate the pusher along an actuating axis, and a substantially cylindrical peripheral skirt, the differential piston being in leaktight sliding contact with the slide cylinder formed by the inside surface of the skirt. The stroke-limiting means advantageously comprise a retaining member formed at the push wall and a fastening element formed by the differential piston, said fastening element being in engagement with the retaining member so as to enable the differential piston to move axially over a limited stroke between a high abutment and a low abutment. The retaining member is advantageously provided with at least one retaining profile, and the fastening element is provided with at least one fastening head suitable for coming into engagement with said at least one retaining profile in the low abutment position. The push wall advantageously has a push outside surface and an inside surface, the fastening element coming into high abutment against said inside surface. The stroke-limiting means are thus formed by the pusher, at its push wall, together with the differential piston.  
         [0016]     In an advantageous embodiment, the differential piston has a disk defining an outer periphery forming at least one sealing lip in leaktight sealing contact with the cylinder of the skirt, the fastening element extending from the disk towards the push wall. The differential piston advantageously has an axial rod co-operating with the valve seat for forming said inlet valve therewith.  
         [0017]     In another aspect of the invention, the differential piston is urged by spring means which are formed integrally with the pusher. The spring means advantageously comprise elastically deformable tabs.  
         [0018]     In another aspect of the invention, the dispenser member has a return spring urging the pusher into the rest position, said spring being formed integrally with the pusher. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]     The invention is described more fully below with reference to the accompanying drawings which show embodiments of the invention by way of non-limiting example.  
         [0020]     In the figures:  
         [0021]      FIG. 1  is a vertical section view through a first embodiment of the dispenser member in the rest state, associated with a fluid reservoir that is shown merely in part;  
         [0022]      FIG. 2  is a view similar to  FIG. 1 , in the actuated position;  
         [0023]      FIG. 3  is a vertical section view similar to the view of  FIGS. 1 and 2 , showing another embodiment of the invention, in the rest position; and  
         [0024]      FIG. 4  is a view similar to  FIG. 3 , in the actuated position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]     The embodiment of the dispenser member of the invention shown in  FIGS. 1 and 2  is shown in association with a receptacle  50  defining an opening in the form of a neck  53  which advantageously has a fixing profile on its outside surface. The receptacle  50  internally defines a fluid reservoir  5 .  
         [0026]     The dispenser member comprises three component elements, namely a body  10 , a pusher  20 , and a piston member  30 . All three parts can be made of a plastics material by injection molding.  
         [0027]     The body  10  has a fixing ring  11  that co-operates with the neck  53  of the receptacle  50 . More precisely, the ring  11  comes into engagement around the neck  53 . The body  10  can also be provided with a self-sealing lip  12  in sealing contact with the inside wall of the neck  53 . A guide band  14  can extend in alignment with the fixing ring  11 . At its top end, the ring  14  is provided with an inwardly-extending rim  141  whose function is given below. The body  10  is also provided with a bushing  13  which extends concentrically inside the guide band  14 . Thus, an annular space is created between the band  14  and the bushing  13 . The top end of the bushing  13  forms a main piston  133  in the form of a sealing lip. The body  10  is also provided with a inlet sleeve  16  which extends concentrically inside the bushing  13 . The top end of the sleeve  16  forms a valve profile or seat  161 . In addition, the body  10  integrally forms a dip tube  15  which extends into the receptacle  50 . The dip tube internally defines an inlet duct  18  which extends to inside the inlet sleeve  16 .  
         [0028]     The pusher  20  has a push wall  21  and a peripheral skirt  22 . The skirt  22  is connected to the push wall  20  at its outer periphery. The push wall  21  has a push outside surface  211  and an inside surface  212 . The push wall  21  and the skirt  22  are in the general shape of an upside-down cup with the end-wall of the cup formed by the push wall  21  and the cylindrical side wall formed by the skirt  22 . The push wall  21  is provided with spring means in the form of elastically deformable tabs or blades  27  which extend from the inside surface  212 . In addition, the push wall  21  is provided with a retaining member  28  which also extends from the inside surface  212 . The retaining member  28  is provided with at least one retaining profile  281  having a retaining edge facing the inside surface  212 . In practice, the retaining member can be provided with a plurality of retaining profiles formed on the outside of a column extending downwards from the push wall  21 .  
         [0029]     The skirt  22  is provided with a dispensing wall  23  and with a guide wall  24 .  
         [0030]     The dispensing wall  23  is connected via its top end to the outer periphery of the push wall  21 . The guide wall  24  is connected via its top end to the bottom end of the dispensing wall  23 . The dispensing wall  23  is provided with an outside surface and with an inside surface  232 . The inside surface is cylindrical at least in part so as to constitute a leaktight slide cylinder. The inside wall  232  is advantageously provided with a swirl system  26  which forms a recessed network in the cylindrical surface  232 . This swirl system can comprise one or more swirl channels and a swirl chamber. In addition, the dispensing wall  23  is provided with a dispensing orifice which passes through the wall so as to extend from the inside surface to the outside surface. The dispensing orifice  25  is centered relative to the swirl system  26 .  
         [0031]     The guide wall  24  is engaged in the annular space formed between the guide band  14  and the bushing  13 . The guide wall forms a shoulder  241  serving to come into abutment under the inwardly-extending rim  141  of the band  14 . Advantageously, the inside surface  242  of the guide wall  24  forms a main cylinder inside which the main piston  133  can be moved in leaktight contact. The guide wall  24  is urged by a spring  40  which pushes the shoulder  241  against the inwardly-extending rim  141 . The spring  40  can advantageously be formed integrally with the pusher in alignment with the guide wall  24 . Thus, the main piston  133  can slide inside the pusher, or more precisely inside the guide wall  24  which internally forms the main cylinder  242 .  
         [0032]     In this example, the piston member  30  forms a differential piston associated with a moving inlet valve member. The piston member  30  has a disk  31  which, at its outer periphery, forms two sealing lips  32  and  33 . The disk  31  and its two lips together form the differential piston. In the rest position shown in  FIG. 1 , the top lip  32  is positioned above the swirl system, whereas the bottom lip  33  is positioned below the swirl system. Thus, the swirl system cannot communicate with the inside of the pusher. In addition, the disk  31  forms an annular recess  311  serving to receive the free ends of the elastically deformable tabs  27  formed by the push wall  21 . Furthermore, the piston member  30  forms a fastening element  39  which extends from the disk  31  towards the push wall  21 . Said fastening element  39  is provided with fastening heads  392  situated at the ends of tabs  391 . The fastening heads  392  are in engagement between the inside wall  212  and the retaining profiles  281  formed by the retaining member  28 . Thus, the heads can move over a limited stroke between the retaining profiles and the inside surface of the push wall. However, the elastically deformable tabs  27  urge the piston member  30  away from the push wall  21 , so that the fastening heads  392  are pushed into engagement with the retaining profiles  281 . The fastening heads  392  can be caused to come into contact against the inside surface  212  by flexing the elastically deformable tabs  27 . Stroke-limiting means thus exist that are constituted by the retaining member co-operating with the fastening element.  
         [0033]     The piston member  30  is thus held captive inside the pusher while being capable of moving axially over a limited stroke. However, the elastically deformable tabs  27  urge the piston member into the rest position, in which the fastening heads are in engagement with the retaining profiles. In addition, the sealing lips  32  and  33  are positioned on either side of the swirl system so as to isolate it. This corresponds to the rest position shown in  FIG. 1 .  
         [0034]     In addition, the piston member  30  also forms an axial central rod  37  which, at its bottom end, has an inlet valve profile  38  which co-operates with the corresponding profile  161  in the sleeve  16  to form the inlet valve therewith. In the rest position, the inlet valve is open.  
         [0035]     Thus, a pump chamber  1  is created between the body, the pusher, and the piston member. The pump chamber  1  is isolated from the outside by the bottom lip  33  but it communicates with the reservoir through the open inlet valve.  
         [0036]     Starting from the rest position shown in  FIG. 1 , it is possible to exert pressure on the push outside surface  211  of the push wall  21 . This causes the pusher and the piston member to move relative to the body. In a first stage, the inlet valve is closed due to the axial rod  37  penetrating more deeply into the sleeve  16  so as to establish sliding leaktight contact. Whereupon, the pump chamber  1  is isolated from the outside. The fluid in the pump chamber is then subjected to an increase in pressure, which causes the piston member  30  to move towards the push wall  21 , against the spring force exerted by the resilient tabs  27 . Thus, the bottom lip  33  moves upwards until it reaches the swirl system  26 . Whereupon, the fluid finds an outlet passageway through the swirl system and through the dispensing orifice. This actuation position is shown in  FIG. 2 . In order to reach this position, it is necessary for the pressure inside the pump chamber to be greater than the stiffness of the elastically deformable tabs  27 , which therefore act as a precompression spring. The piston member  30  can move towards the push wall  21  until the fastening heads  392  come into abutment against the inside surface  212 . In this position, which is shown in  FIG. 2 , the bottom sealing lip  33  of the differential piston is positioned at the swirl system. As soon as the pressure inside the chamber decreases again, the piston member  30  can, once again, move away from the push wall  21  under the drive from the resilient tabs  27 . Finally, the piston member  30  returns to its rest position shown in  FIG. 1 .  
         [0037]     In the second embodiment shown in  FIGS. 3 and 4 , the receptacle  50 , the body  10 , and the piston member  30  can be identical to those in  FIGS. 1 and 2 . The pusher  20  has a dispensing wall  23  and a guide wall  24  inwardly forming a main cylinder for the main piston  133 . The push wall  21  also forms elastically deformable tabs  27  and a retaining member  28 . The displacement of the piston member inside the pusher  20  can be identical to that of the embodiment in  FIGS. 1 and 2 . However, the inside surface of the dispensing wall  23  is not formed with a swirl system, but solely with a through duct  25 , which does not form the dispensing orifice. In this case, the pusher  20  is associated with a cap  60  which covers the push wall  21  and the actuating wall  23 . By way of example, the pusher can be force-fitted inside the cap. The cap  60  comprises an outer peripheral ring  63  which extends concentrically around the dispensing wall  23  in clamping contact therewith. The ring  63  is formed with a dispensing orifice  65 . Furthermore, the outside surface of the dispensing wall  23  is formed with a swirl system  26  which is centered on the dispensing orifice  65 .  
         [0038]     The piston member  30  is held captive inside the pusher while being allowed a limited degree of freedom to move axially. It should also be noted that the precompression spring is formed integrally with the pusher. In addition, the piston member being held captive, and its movement being limited are achieved entirely by the pusher and by the piston member, without any additional part being necessary.