Patent Publication Number: US-2009230156-A1

Title: Automatically Closing Dispenser Head

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to an automatically closing dispenser head for a pressurized container with a dispensing valve for dispensing a medium, in particular viscous, foaming and/or gel-like products, wherein the dispenser head has a dispensing opening closable by a closure element, an opening mechanism by means of which, in the mounted state, the dispensing valve of the pressurized container can be opened, and a channel that opens into the dispensing opening for the medium. The channel comprises at least a first channel section and a second channel section. By pressure being applied onto the actuating element, the opening mechanism is actuated and the closure element in the form of a closure piston and the second channel section are moved relative to one another such that the closure element is moved out of the dispensing opening so as to release the dispensing opening. 
     Conventional pressurized containers with dispenser heads, for example, for foaming shaving creams and gels, usually have a dispensing opening that cannot be closed so that, after use, it often happens that medium will continue to flow or to foam even though the actuating element is no longer actuated; this leads to unpleasant residues in the area of the dispensing opening that dry up and contaminate newly dispensed fresh medium when using the pressurized container again. Moreover, as a result of dried and clotted medium the dispensing opening often becomes clogged. 
     In order to avoid these disadvantages, the patent application EP 1 295 812 A1 discloses an automatically closing dispenser head for a pressurized container of the aforementioned kind in which the dispensing opening can be closed and opened by means of a closure element. Upon exerting pressure onto an actuating element, the opening mechanism is actuated and the closure element and the second channel section are moved relative to one another. In this way, on the one hand, the dispensing valve is opened so that the pressurized medium can flow into the channel. However, the medium can only exit through the dispensing opening once the closure element has released the second channel section. By spring means, for example, a partially elastically deformable housing of the dispensing head, the respective elements can return into their original position relative to one another and to the pressurized container as the pressure being exerted onto the actuating element decreases so that the dispensing valve as well as the dispensing opening are closed again. In this way, leakage and post-foaming are effectively counteracted. 
     However, it is a disadvantage that in the area of the dispensing opening there are still residues of the dispensed medium. Moreover, reliably dosing the dispensing opening is a problem. 
     U.S. Pat. No. 5,205,443 discloses a dispensing head for the medium in which the closure element is designed to be elastic. An actuating element acts in a shaft-like area in front of the dispensing head of the closure element on the closure element and, upon actuation, can cause bending of this shaft causing the dispensing head to be moved into the interior of the housing to thereby release a dispensing opening. Upon subsequent release of the actuating element, the closure element is returned into the dispensing opening causing still adhering residues of the medium to be forced into the dispensing opening so that the dispensing opening becomes clogged and post-foaming is unavoidable. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to configure an automatically closing dispenser head for a pressurized container of the aforementioned kind in such a way that residues of the medium to be dispensed are effectively avoided and the dispensing opening can be closed reliably. 
     In accordance with the present invention, this is achieved in that the automatically closing dispensing head is characterized in that the closure element is a movable closure piston that is provided with centering projections that are arranged on the outer piston wall and spaced at a distance from one another and movable with the closure piston, wherein between individual centering projections flow passages for the medium are provided and wherein on an end face of the closure piston facing away from the dispensing opening an elastic spring area is provided that is delimited at its end by a head section that interacts with the actuating element, wherein the head section has a rounded cross-sectional configuration and wherein the actuating element, during opening and closing movement of the closure piston into the opening position or closing position, glides along the rounded head section. In this connection, the rounded portion of the head section is matched to the movement path of the actuating element. 
     In this way, an automatically closing dispenser head for a pressurized container is provided by means of which a medium can be dispensed in a very clean way. This is in particular the result of positional deviations of the closure piston relative to the housing parts being reliably avoided by the presence of the centering projections that in the second channel section are supported on the inner wall of the second channel section during the entire movement of the closure piston when moving into the opening position as well as when moving into the closing position; this has the result that, in comparison to the aforementioned configuration of the prior part, no positional imprecisions during the closing step occur in the area of the dispensing opening so that the closure piston can be moved reproducibly and precisely into the opening and closing positions. This causes residues remaining in the dispensing opening to be reliably returned into the first channel section upon transfer of the closure piston from its opening position into the closing position. Therefore, in the outer area of the dispensing opening of the dispenser head only minimal amounts of be dispensed medium will remain, if at all, that can be removed by the user with simple means, for example, simply by wiping with his finger or by rinsing off. The risk of clogging of the dispensing opening is therefore reliably counteracted. 
     Dispensing of the medium is not impaired because flow passages are provided between the individual centering projections. The same holds true also for return of the medium once the pressure onto the actuation element decreases and the closure piston moves into its closing position. In order to provide a centering action that is uniform about the circumference, the centering projections are preferably arranged in uniform distribution about a circumferential section of the closure piston. It has been found in this connection that, for example, four centering projections that are uniformly distributed about the circumference provide a precise movement and centering action of the closure piston. In this connection it must be ensured that during the entire closure movement no tilting moments are possible across the length of the closure piston so that the centering elements are located near the leading end of the closure piston. For this purpose, the leading end can also have a cross-sectional widened section that extends about the circumference of the closure piston so that it is provided with an enlarged circumferential section on which the centering elements are arranged. This also has the result that at this location an increase of the flow rate of the medium to be dispensed is realized. 
     It is especially preferred that at the leading end, i.e., the end of the closure piston that is facing the dispensing opening, a sealing element is injection molded, preferably by means of an inner central supply conduit within the closure piston and supply conduits that extend perpendicularly thereto and open into the outer surface of the closure piston. Such a sealing material is comprised, for example, of a soft plastic material, for example, TPE (thermoplastic elastomer) or silicone. The closure piston can be made, for example, from ABS (acrylonitrile butadiene styrene), PP (polypropylene), or POM (polyoxymethylene) material, i.e., hard plastic materials. 
     In order to assist in the return of the material to be dispensed, the second channel section has a valve seat in which the closure piston with the sealing element is to be completely seated in its closing position. For a slight slanted orientation of the closure piston relative to the horizontal, a position is to be assumed by the closure piston wherein an upper area of the end of the closure piston at the dispensing side is arranged at a distance from the dispensing opening but otherwise does not project past the housing of the dispenser head in the area of the dispensing opening. Preferably, the closure piston is positioned within the valve seat such that its leading end is flush with the outer surface of the housing so that product residues can be easily removed. In this way, material still adhering at this location can be returned by the seal and the valve seat into the lateral channel section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is an embodiment of a dispenser head (schematically shown with a view of its interior) in the closed state of the closure piston. 
         FIG. 2  is an illustration analog to  FIG. 1  with the closure piston in the open position. 
         FIG. 3  is a detail view of a cross-sectional illustration of the dispenser head of the embodiment according to  FIG. 1  in the area of the dispensing end and of the closure piston. 
         FIG. 4  is an illustration analog to  FIG. 3  with the closure piston in the opening position. 
         FIG. 5  is an illustration according to  FIG. 3  illustrating the angled orientation of the closure piston relative to the horizontal. 
         FIG. 6  is a cross-sectional illustration in accordance with the section line VI-VI of  FIG. 5 . 
         FIG. 7  shows a detail view of the end of the closure piston that is facing away from the dispensing opening and is provided with spring element and actuating element. 
         FIG. 8  is a detail view of the closure piston (in section) with inner central conduit for injection molding the front end seal and the spring element. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The drawings identify parts that basically operate in the same way with identical reference numerals. The dispenser head is generally identified by  1  and is preferably a unitary part of the pressurized container, not illustrated. The container has a housing  2  as well as a dispensing valve, not illustrated in detail and only schematically shown as valve V in  FIGS. 1 and 2 , for dispensing a medium, for example, viscous, foaming and/or gel-like products. This dispensing valve is assigned to the interior of container in which the medium is contained and can be operated by an opening mechanism. 
     The dispenser head has a dispensing opening that is comprised of a first channel section  4  and a second channel section  5  in communication with the interior. The second channel section  5  has correlated therewith the closure element formed as a closure piston  6  that controls the dispensing opening  3 . The closure piston  6  is movable relative to the channel section  5  so that it can be moved from its closing position ( FIG. 1 ) into its opening position ( FIG. 2 ). 
     In order to be able to carry out this movement, an actuating element  7  is provided that is forced from its rest position ( FIG. 1 ) into the actuating position and is thus pivoted. This actuating element  7  actuates at the same time the opening mechanism (indicated schematically by the arrow M connecting valve V and the actuating element  7 ) with which the dispensing valve is opened. 
     As is disclosed in more detail in  FIGS. 3 ,  4 ,  5 ,  6 , and  8 , at the leading end of the closure piston  6  a section  6 . 1  is provided that has centering projections  6 . 2  that are supported on the inner wall of the second channel section  5  in the housing. In the illustrated embodiment, a total of four centering projections  6 . 2  are uniformly distributed about the circumference and between them flow passage  6 . 3  for the product to be dispensed are provided. In the leading area of the second channel section  5 , i.e., at its end that opens into the dispensing opening  3 , the housing is provided with a valve seat  3 . 1 . 
     This valve seat is correlated with the leading end of the closure piston  6 . This leading end of the closure piston  6  is provided with an injection-molded seal  8  made of soft plastic material. The leading piston head  6 . 4  of the closure piston  6  has a configuration that is congruent to the conical design of the valve seat so that it can be inserted completely into the valve seat, as illustrated in more detail in  FIG. 3 . The upper part shown in  FIG. 3  is positioned at a distance relative to the dispensing opening  3  (its front end). Nonetheless, in the closed state the leading piston head  6 . 4  as a whole is arranged in a recessed position so that residues of the dispensed medium can be easily wiped off with a finger and, subsequently, the externally accessible parts of the valve seat can be rinsed off. In this way it is reliably prevented that residues that can dry up or clot remain in the area of the dispensing opening  3 . 
     The return movement of the closure piston from its opening position illustrated in  FIG. 4  into the closing position of  FIG. 3  causes residues that are still remaining to be returned into the inner channel section  5 . 
     The end of the closure piston facing away from the dispensing opening  3  has a spring element  9  of soft plastic material. The spring element  9  is provided in the direction facing the actuating element  7  with a head section  10  that has a rounded gliding surface  10 . 1 . The spring element  9  is at the same time also a sealing element so that product cannot exit from the container at this location. The actuating element  7  has a correspondingly congruently shaped contact surface  7 . 1  that during the course of actuation, i.e., when suppressing the actuating element  7 , glides along the gliding surface  10 . 1 . As a result of the rounded configuration only relatively minimal friction forces are present; this also has the effect that no tilting moment can be transmitted onto the closure piston (such disadvantageous tilting moments occur in prior art devices). 
     Moreover, the desired almost horizontal position of the closure piston can be realized even though the actuating element is acted on in the vertical direction. Preferably, a longitudinal center axis of the closure piston is oriented such that an angle a of less than 15 degrees to the horizontal is provided; see  FIG. 5 . 
     As a result of the minimal friction forces, the reduced tilting moment, and the provided centering projections  6 . 2 , the closure piston can be transferred very precisely into the respective opening or closing position. The inventive configuration provides optimized sealing behavior and positioning in the closing position with simultaneous return of the medium. 
     In  FIG. 8 , the inner central conduit  6 . 5  is illustrated that communicates with transverse conduits  6 . 6  for injection-molding the seal  8  and the spring element  9 . 
     The specification incorporates by reference the entire disclosure of German priority document 10 2007 044 180.2 having a filing date of Sep.  15 ,  2007 . 
     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.