Dispensing – With discharge assistant – With movable nozzle interconnected therewith
Reexamination Certificate
1998-10-28
2001-01-09
Shaver, Kevin (Department: 3754)
Dispensing
With discharge assistant
With movable nozzle interconnected therewith
C222S321900
Reexamination Certificate
active
06170713
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to the field of precompression pumps. More particularly, the present invention is directed to a precompression pump used for dispensing, e.g., personal care products, from a container or bottle upon which the pump is mounted.
2. Description of the Related Art
Precompression pumps are known in the art. A precompression pump is a pump in which the outlet valve for the pump chamber opens in response to a predetermined pressure level within the pump chamber. Often, this is accomplished by providing an outlet valve having a surface upon which pressure in the pump chamber acts, and which is biased in a way that the outlet valve only opens when the pressure in the pump chamber is of a sufficiently high level. This type of pump is particularly useful for dispensing personal care products in a fine mist without dribbling.
A problem can arise in precompression pumps of the type described above during priming of the pump. When the pump chamber is in an unprimed condition—i.e., is filled with air instead of the liquid to be dispensed—it is necessary to evacuate air from the pump chamber in order to draw the liquid to be dispensed into the pump chamber. However, the air in the pump chamber can act as a compressible fluid. As a result, in certain precompression pump designs air in the pump chamber is compressed during the downstroke of the pump piston, and the pressure in the pump chamber does not achieve a sufficiently high level to open the outlet valve and release the air in the pump chamber through the pump nozzle. It is therefore difficult to evacuate the air from the pump chamber and to draw liquid into the pump chamber for dispensing. The result is that an undesirable number of “strokes to prime” may be necessary to operate the pump, if the air is not released from the pump chamber in some way other than through opening of the outlet valve.
Several patents describe mechanisms for assisting in the evacuation of air from a pump chamber to allow the pump to be primed. U.S. Pat. Nos. 3,746,260; 3,774,849; 4,051,983 and 4,144,987 show various mechanisms used to evacuate air from the pump chamber of a precompression pump. However, many of these mechanisms are unsatisfactory in that they can vary the volume of the dose, can cause wear or fatigue in the operating parts of the pump, or are difficult to mold. U.S. Pat. No. 5,192,006 shows a pump which includes a feature for evacuating air from the pump chamber. This pump, however, uses friction-operated inlet and outlet valves which can be disadvantageous for several reasons. First, in order for the friction-operated valves to operate properly, several parts must be closely toleranced to ensure proper frictional fits. In addition, the functional characteristics of the pump can vary depending on variations in the frictional fit between parts. Furthermore, any variations in tolerancing can result in frictional fits which can prevent the valves from opening and/or can cause the valves to remain open when they are intended to be closed. Finally, the design of the parts necessary to achieve the frictional fits involves detailed, and potentially expensive, molding equipment.
SUMMARY OF THE INVENTION
The present invention is advantageous in that it provides a precompression pump which is of a simple design, which ensures evacuation of air from the pump chamber to the spray nozzle, and which does not require close tolerancing and complicated molded parts to ensure proper and effective operation.
The present invention includes a pump housing defining a pump chamber in which a pump piston reciprocates. A pump spring biases the pump piston upwardly or axially outwardly. A gravity-biased inlet valve is located between the inlet or dip tube and the interior of the pump chamber. This inlet valve can be either a conventional ball-check valve or can be a gravity-biased stem valve. A spring-biased outlet valve is located between the interior of the pump chamber and the spray nozzle. This outlet valve opens in response to a specific internal pressure within the pump chamber. The outlet valve can be either a conventional ball-check valve, or a stem valve. The stem valve can have a conical sealing surface which cooperates with a conical sealing surface on the pump piston. In either case, the only contact between the outlet valve and the piston in which the outlet valve is housed is the fit caused by the outlet valve spring bias. At least one of either the inlet valve or the outlet valve has an engagement piece which interacts with the other valve of the pump at the bottom of the downstroke of the pump piston. This interaction opens the outlet valve, against the bias of the valve spring, thereby evacuating any air or liquid trapped in the pump chamber at the bottom of the downstroke of the pump. As a result, any compressed air in the pump chamber is mechanically evacuated from the pump chamber through the outlet valve, and the pump chamber is therefore capable of being filled with liquid from the container or bottle for subsequent spraying through the spray nozzle.
Several different variations on the design of the inlet and outlet valves are contemplated, and several variations are disclosed herein, although these variations do not limit the inventions which are contemplated within the scope of the invention.
REFERENCES:
patent: 3746260 (1973-07-01), Boris
patent: 3774849 (1973-11-01), Boris
patent: 4051983 (1977-10-01), Anderson
patent: 4144897 (1979-03-01), Kishi
patent: 4228931 (1980-10-01), Ruscitti et al.
patent: 4694976 (1987-09-01), Schuetz
patent: 5092495 (1992-03-01), Andre
patent: 5192006 (1993-03-01), Van Brocklin et al.
patent: 5638996 (1997-06-01), Montaner et al.
patent: 5671874 (1997-09-01), Behar et al.
Bui Thach H
Emson, Inc.
Kenyon & Kenyon
Shaver Kevin
LandOfFree
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