Dispensing – Resilient wall – Supply container delivering to receiving chamber
Reexamination Certificate
2000-05-04
2001-10-09
Derakshani, Philippe (Department: 3754)
Dispensing
Resilient wall
Supply container delivering to receiving chamber
C222S321700
Reexamination Certificate
active
06299029
ABSTRACT:
The present invention relates to a pump and to a receptacle containing a liquid, for example a cosmetic cream, and fitted with such a pump.
BACKGROUND OF THE INVENTION
French patent 2 728 809 discloses a pump comprising a pushbutton displaceably mounted on a support which is secured to the receptacle containing the substance to be dispensed, the pushbutton having a circularly cylindrical central duct provided with radial openings at its bottom end, the support defininq an annular pump chamber of variable volume around said duct. A diaphragm made of elastomer is mounted on the support. The diaphragm has a circularly symmetrical central portion in the form of a sleeve that is open at its top end and closed at its bottom end. The central duct of tile pushbutton is inserted in the diaphragm until it bears against the end wall of the sleeve.
The diaphragm thus constitutes a resilient return member enabling the pushbutton to be returned to its initial position after a quantity of substance has been dispensed.
Also, during the return movement of the pushbutton, the diaphragm isolates the pump chamber by pressing against the central duct, thereby preventing air returning into the chamber.
Such a pump presents the advantage of having only a small number of parts and thus of being of relatively low cost to manufacture.
Nevertheless, that known pump does not provide complete satisfaction, and the Applicant company has observed that the pushbutton tends to jam and/or to dispense non-uniform quantities of substance.
In addition, such a pump suffers from difficulties in priming.
OBJECTS AND SUMMARY OF THE INVENTION
The present invention seeks to improve the reliability of the operation of a pump of the above-defined type, i.e. comprising a moving member mounted to move relative to a support, the moving member having a central duct into which the substance to be dispensed penetrates via at least one opening, the support cooperating with the moving member to define a variable volume pump chamber around said central duct, the pump also having a diaphragm having a central portion in the form of a sleeve that is open at its top end and closed at its bottom end, said central duct being inserted in said central portion, the diaphragm being organized in such a manner as to isolate the opening(s) of the pump chamber when the volume of the pump chamber increases and the substance is sucked into it.
The invention achieves this by the fact that the bottom portion of the central portion of the diaphragm presents, at least over a sector of its periphery, a preferred deformation zone, advantageously constituted by a thin zone.
By means of the preferred deformation zone(s), it is possible to make a pump in which the central portion of the diaphragm exerts a relatively large return force on the moving member so as to return it to the rest position, without that preventing the substance contained in the pump chamber from reaching the central duct so as to be dispensed when the user presses on the moving member.
In a particular embodiment, the bottom portion of the central portion of the diaphragm has at least two diametrically opposite thin zones.
Still in a particular embodiment, the thin zone is formed by reducing the thickness of the diaphragm by at least 20%, and preferably by at least 25%.
Advantageously, the inside surface of the central portion of the diaphragm presents an inwardly-directed step.
Preferably, said step is situated level with the top end of the preferred deformation zone(s).
In a particular embodiment, the diaphragm has a flexible lip suitable firstly for isolating the pump chamber from the source of substance when the volume of said pump chamber decreases, and secondly for enabling substance to enter into said pump chamber when the volume thereof increases.
In a particular embodiment, said flexible lip is connected to the central portion of the diaphragm by forming a downwardly open annular trough, and the support includes an inner skirt having its top end bearing against the end wall of said trough to retain the diaphragm when the moving member is moved downwards to decrease the volume of the pump chamber.
Preferably, said inner skirt has openings at its top end, the openings being of a height that is less than the height of the flexible lip, said openings enabling the substance to reach the pump chamber when the volume thereof increases and the flexible lip moves away from the inner skirt.
In a particular embodiment, the central portion of the diaphragm is connected at its top end to an annular portion whose width and thickness are selected in such a manner as to improve retention of the diaphragm when said central portion is stretched.
Preferably, the thickness of the above-mentioned annular portion, prior to the diaphragm being assembled in the pump, is greater than or equal to the thickness of the diaphragm in its central portion.
Preferably, the above-mentioned annular portion, prior to the diaphragm being assembled in the pump, is at least 1.5 times wider than it is thick, and preferably twice as wide as it is thick.
Advantageously, the end wall of the central portion of the diaphragm, prior to the diaphragm being assembled in the pump, presents substantially the same thickness as the side wall of the central portion of the diaphragm outside said preferred deformation zone(s).
Preferably, the thickness of the end wall corresponds to within 20% to the thickness of the side wall of the central portion of the diaphragm, outside said preferred deformation zone(s), prior to the diaphragm being mounted in the pump.
In a particular embodiment, the height of the above-mentioned flexible lip is greater than or equal to tie height of the central portion of the diaphragm, prior to the diaphragm being assembled in the pump.
In a particular embodiment, the flexible lip is of thickness that increases going towards the top end of the diaphragm.
In a particular embodiment, the outside surface of the flexible lip presents, starting from its bottom end, a bottom portion that is circularly cylindrical about the axis of the central portion of the diaphragm, followed by an upper portion that is conical and diverges towards the top end of the diaphragm, which upper portion is connected via a shoulder to an annular rib.
Preferably, the inside diameter of the flexible lip is equal to the outside diameter of the inner skirt, ignoring manufacturing tolerances.
Also preferably, the clearance between the flexible lip and the inner skirt is negative or zero; this ensures that the flexible lip is lightly clamped against the inner skirt.
In a particular embodiment, when the moving member is at rest, the length of the central portion of the diaphragm after being assembled in the pump is greater than or equal to 1.5 times its initial length prior to assembly in the pump, and is preferably greater than or equal to twice said initial length, and more preferably greater than or equal than 3 times said initial length.
In a particular embodiment, when tile moving member is fully depressed, the length of the central portion of the diaphragm is greater than or equal to twice the initial length of the diaphragm prior to assembly in the pump, is preferably greater than or equal to 3 times said initial length, and more preferably greater than or equal to 4 times said initial length.
In a particular embodiment, at least one of the diaphragm and the central duct is shaped to prevent an annular zone forming between the diaphragm and the central duct that would prevent the substance contained in the pump chamber from flowing via said central duct when the volume of the pump chamber decreases.
Preferably, at least one of the diaphragm and the central duct is shaped so as to bear against the other of the central duct and the diaphragm at predetermined locations of its periphery, at least during displacement of the moving member relative to the support.
Preferably, at least one of the diaphragm and the central duct has portions in relief against which the other of the central duct and the diaphragm comes to bear, at least duri
Derakshani Philippe
L'Oreal
Oliff & Berridg,e PLC
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