Dispensing – Resilient wall – Supply container delivering to receiving chamber
Reexamination Certificate
1999-01-25
2001-02-20
Shaver, Kevin (Department: 3754)
Dispensing
Resilient wall
Supply container delivering to receiving chamber
C222S214000, C222S101000, C222S309000
Reexamination Certificate
active
06189740
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the dispensing arts. It finds particular application in conjunction with antiseptic soap dispensers for accurately dispensing discrete doses of soap, hand lotions, creams, and the like, into the palm of a user, and will be described with particular reference thereto. It should be appreciated, however, that the invention is also applicable to the dispensing of other fluid, viscous, and pasty materials, such as food products, where accurate dosage is desired.
Hand-operated dispensers are widely used for delivery of liquid soaps, hand lotions, creams, and the like. These are typically mounted on a wall and consist of a housing and a dispensing mechanism. The fluid is stored in a replaceable reservoir, such as a plastic container, within the housing and delivered, as needed, by actuating the dispensing mechanism.
A wide variety of dispensing mechanisms have been developed for dispensing discrete doses of fluid. One type of dispenser employs a resiliently flexible dispensing tube or pathway which is compressed between two rigid members to deliver the fluid. U.S. Pat. No. 4,667,854 to McDermott, et al., U.S. Pat. No. 4,178,975 to Crespi, and U.S. Pat. No. 5,377,871 to Banks, et al. disclose dispensers in which one of the rigid members is a roller. The roller of McDermott, et al., for example, is mounted on an arm of a Y-shaped cam. The other arm of the Y is spring biased. Pressure on a bar on the front of the dispenser causes the cam to rotate and the roller is urged against an upper end of a flexible tube, compressing the tube between the roller and a block. Continued pressure on the bar causes the roller to move progressively down the tube, forcing the liquid out of the end of the tube as it descends. When the bar is released, the spring returns the roller and cam to their original positions.
A user operating such dispensers typically holds the palm of the hand beneath the dispenser to receive the dose of soap. However, during actuation of the dispenser, the palm of the hand generally moves relative to the end of the flexible tube, and some of the soap may not be received in the palm. Wastage of soap often results. More importantly, for antiseptic soaps, decontamination is only assured when a complete dose is applied to the hands. Soap that trickles through the fingers or misses the hand completely does not contribute to thorough decontamination.
In addition, conventional roller-type dispensers suffer other disadvantages. Typically, the roller follows a return path that is the reverse of the path traveled during dispensing. Thus, the roller moves back up the flexible tube, compressing the tube. This tends to draw air into the tube behind the roller. It is desirable to keep air which may be contaminated with external bioburden out of the container. Although the soaps generally contain preservatives, these may be overwhelmed if an excess of bioburden enters the container and remains in contact with the soap for an extended period.
Such a return path also lengthens the time between actuations of the dispenser. Until the roller has returned to the at-rest position, leaving the top of the tube open, soap does not begin to flow down from the container into the tube, ready for further dispensing. If the dispenser is, actuated before the tube has refilled, an incomplete dose will be administered and decontamination cannot be guaranteed.
For some antiseptic soaps, a sizable dose is recommended for complete decontamination. Most dispensers have a fixed nominal dose which is dispensed in a single actuation. When larger doses are required, the dispenser is typically provided with a notice, directing the user to dispense two or more shots of the soap. This is not only time consuming, but often results in an insufficient dose. Because the dispenser frequently takes a few seconds for the pathway to refill, the second actuation will not yield the desired dose if initiated too quickly.
To overcome this problem, some dispensers provide a volume regulator, which allows for different size doses to be dispensed. U.S. Pat. Nos. 4,778,085 to Bush, et al. and 3,288,332 to Etter, et al. disclose examples of such volume regulators. To allow for different size doses and different soap viscosities, volume regulators tend to be infinitely adjustable between minimum and maximum settings. The operator who sets the regulator may therefore set it too low, resulting in an inadequate dose, or too high, resulting in unnecessary wastage of soap. Moreover, a user may subsequently adjust the regulator for a smaller dose and fail to return the regulator to the correct setting for assured decontamination.
There remains a need, therefore, for soap dispenser which dispenses discrete doses of soap accurately and reproducibly, without ingress of potentially contaminated air into the dispenser. The present invention provides a new and improved soap dispenser which overcomes the above-referenced problems and others.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a dispenser for discharging a liquid is provided. The dispenser includes a housing including a front cover and a back plate. A reservoir, for containing the liquid, is removably mounted within the housing. The reservoir includes a container and a flexible tube connected at an upstream end to the container. A valve selectively closes a downstream end of the tube. A roller assembly is pivotally mounted in the housing, and includes a roller bar rotatably mounted on an assembly body. A platen is moveably connected to the front cover of the housing such that pressure on the platen moves the platen towards the roller assembly, the platen compressing the upstream end of the tube between the platen and the roller bar and camming the roller bar towards the downstream end of the tube.
In accordance with another aspect of the present invention, a method of dispensing an antiseptic liquid from a reservoir without drawing contaminated air into the reservoir is provided. The method includes compressing a flexible tube between a platen and a roller to seal off an upper portion of the tube, the tube being connected at an upper end to the reservoir of the liquid and having a valve at a lower end. The method further includes moving the roller progressively down the tube toward the downstream end, the tube being compressed progressively adjacent the roller, the roller exerting a pressure on the liquid at the downstream end of the tube which causes the valve to open to dispense the liquid. The method further includes removing the compression on the tube adjacent the downstream end of the tube such that liquid drawn from the reservoir into the tube behind the roller remains in the tube and blocks ingress of air through the valve.
One advantage of the present invention is that it dispenses measured doses of an antiseptic soap.
Another advantage of the present invention is that external bioburden is not drawn into the tube. The soap remaining in the tube contributes to blocking ingress of air into the dispenser as the dispensing mechanism returns to its at-rest position.
Yet another advantage of the present invention is that the dispenser has a short recycle time, allowing accurate dispensing of soap at frequent intervals.
Still another advantage of the present is that both small and large doses of soap may be dispensed with a high degree of reproducibility.
A further advantage of the present invention is that a low actuation force dispenses soap from the dispenser.
A yet further advantage of the present invention is that the dispenser provides for minimal distortion and wear of the flexible tube.
Still further advantages reside in that the soap is dispensed directly into the users hand, assuring that a full dose is applied and soap is not wasted.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
REFERENCES:
patent: 3066832 (1962-12-01), Rosse
Alsberg Keith D.
deBeers James D.
Taylor Jon B.
Wade Allan E.
Cartagena Melvin A.
Fay Sharpe Fagan Minnich & McKee LLP
Shaver Kevin
Steris Inc
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