Fountain toothbrush

March 17, 1970

R. H. HE1SKELL ET AL

3,501,243

FOUNTAIN TOOTHBRUSH

Filed Nov. 9. 1966

<img file="US3501243A_D0001.tif" />

United States Patent Office

3,501,243

Patented Mar. 17, 1970

3,501,243

FOUNTAIN TOOTHBRUSH

Raymond H. Heiskell, 30 Laurel Court, San Mateo, Calif.

94402, and William A. Anderson, 1659 29th Ave., San Francisco, Calif. 94122 5

Filed Nov. 9, 1966, Ser. No. 593,023 Int. Cl. A46b 11/02

U.S. Cl. 401—131 5 Claims

ABSTRACT OF THE DISCLOSURE

An improved fountain toothbrush having a replaceable dentifrice reservoir in the form of a simple toothpaste tube.

Many attempts have been made in the past to provide acceptable fountain toothbrushes as indicated by the devices shown in the following U.S. patents: Wallace 1,610,831, Aiken 2,283,781, Bair 2,328,048, Lamonde 2,527,741, Speig 2,621,352, and Rivero 2,900,650. These devices have been so complicated, however, and have operated so inefficiently that none of the devices has enjoyed any substantial commercial success.

In accordance with this invention, we have now provided a very simple fountain toothbrush which operates much more efficiently than the devices known heretofore and which can be manufactured as economically as the presently available separate toothbrush and toothpaste tube. These advantages are obtained with our fountain toothbrush because we provide a resiliently deformable dentifrice reservoir with means for introducing air into the end of the reservoir opposite to the toothbrush bristles. Dentifrice may be dispensed from the reservoir simply by compressing the reservoir, and when the reservoir is released, it expands resiliently to draw in air. Since the air drawn into the reservoir is introduced into the upper end of the reservoir, the reservoir may be compressed repeatedly to dispense repeated quantities of dentifrice. During the subsequent uses, the air in the reservoir is positioned away from the discharge end of the reservoir so that the air in the reservoir does not interfere with subsequent dispersing operations, thereby permitting the entire quantity of dentifrice in the reservoir to be used.

In different forms of the invention, the air is introduced into the upper end of the reservoir in different ways. Direct mechanical introduction may be provided by providing a check valve in the upper end of the reservoir. Preferably, the check valve is formed as an integral blade of the resilient material forming the reservoir where the blade closes to seal the upper end of the reservoir when the reservoir is compressed and then opens to admit air into the reservoir, thus permitting the reservoir to resume its original shape. '

In the preferred form of the invention, air is introduced into the upper end of the reservoir by drawing air in through the discharge opening in the bottom and providing a sufficient amount of a liquid diluent in the dentifrice in the reservoir that air bubbles will flow upwardly through the dentifrice from the discharge opening. In this form of the invention, the quantity of liquid diluent is controlled very carefully so that the dentifrice will have a viscosity low enough to permit this upward flow of air bubbles, but high enough to prevent the flow of the dentifrice out of the discharge opening in the lower end of the reservoir.

In this preferred form of the invention, the mounting of the fountain toothbrush in a brush-down position between uses is particularly important in providing efficient operation because the dentifrice always flows toward the discharge opening during periods between uses of the device.

Other features and advantages of the invention will become apparent from the following description read in conjunction with the attached drawing in which:

FIG. 1 is a view in side elevation of the fountain toothbrush of this invention illustrating in phantom outline the brush portion of the fountain toothbrush within the base of the device;

FIG. 2 is a vertical sectional view of the fountain toothbrush of FIG. 1, taken along the plane 2—2 of FIG. 1 and illustrating the condition in which the device is sold;

FIG. 3 is a vertical sectional view of the fountain toothbrush of FIGS. 1 and 2 illustrating the manner in which the device is used, and;

FIG. 4 is a sectional view of a fragment of an alternative form of the invention illustrating a check valve for mechanically introducing air into the upper end of the dentifrice reservoir.

Referring now in detail to the drawing and particularly to FIG. 1, the preferred form of our invention illustrated therein includes a rigid base 10 having an interior chamber 12 provided with vent ports 14. The base 10 has four integrally formed feet 16 by which the device is supported in upright position on any horizontal surface. The upper end of the base 10 has a mouth 18 in which the remainder of the components may be mounted.

As illustrated in FIGS. 2 and 3, the fountain toothbrush includes a dentifrice reservoir 20 which is removably mounted in mouth 18 of the base 10. The dentifrice reservoir 20 is formed of a vapor impervious plastic material which is resiliently deformable so that the reservoir may be compressed as illustrated in solid lines in FIG. 3, but will return to its original shape under the influence of its own resiliency as illustrated in phantom outline in FIG. 3. Suitable plastic materials from which the reservoir 20 may be made include relatively thick layers of polyvinyl chloride or isotactic polypropylene 22 preferably covered on the inside by a layer 24 of a barrier material such as the plastics sold by the Dow Chemical Company under the trademark Saran. A body of dentifrice 26 explained in greater detail hereinafter is provided in the reservoir 20 and dispensed from the reservoir during use of the device.

As illustrated in FIG. 2, the lower end of the reservoir 20 has a threaded neck portion 28 which is covered by a closure cap 30 at the time when the device is sold. A toothbrush 32 is loosely mounted in the cap 10 below the closure cap 30 at the time the device is sold, and as illustrated in FIG. 3, the toothbrush 32 is provided with an interior threaded portion 34 which is threaded onto the neck 28 in place of the closure cap 32 when the device is to be used. The toothbrush 32 has two rows of bristles 36 converging toward each other with a passageway 38 extending from between the bristles 36 to the threaded portion 34 of the toothbrush in communication with the interior of the reservoir 20 as illustrated in FIG. 3;

As indicated above, the body of toothpaste 26 is blended with a sufficient quantity of liquid diluent so that air bubbles in the body of dentifrice 26 will flow upwardly in the cavity 20 while the dentifrice 26 will not flow downwardly through the passageway 38 under the influence of gravity alone. The liquid diluent which is employed is preferably water, and the quantity of diluent used should be selected carefully to give a viscosity for the dentifrice which is within the limits indicated above. Since dentifrices used in devices of this type are non-Newtonian fluids, it is difficult to define the precise viscosity of the dentifrice in a way which is reproduceable experimentally. However, the desired viscosity of the dentifrice has

3,501 been determined employing a Brookfield viscosimeter using spindle #7 rotating at six revolutions per minute. Under these conditions, four samples of dentifrice were tested for viscosity as follows:

Example No.: Viscosity (centipoises) 5

1__________—_____________________ 287,000

2_____ 224,000 ___________________________________ 140,000

4___________________________________ 30,000

Example #1 is the viscosity of a commercially avail- ¹⁰ able toothpaste sold under the trademark Colgate, and this dentifrice is much too viscous for any practical use in the fountain toothbrush of FIGS. 1-3. The dentifrice of Example #2 is the same dentifrice tested in Example 15 #1 but diluted with water to provide a moderately heavy flowable paste. The viscosity of the dentifrice forming Example #2 is sufficiently high that the dentifrice is too viscous for use in a device where the diameter of the passageway 38 is one-sixteenth of an inch, but the denti- 20 frice tested in Example #2 is sufficiently fluid to be used where the diameter of the passageway 38 is one-eighth of an inch. The dentifrice tested in Example #3 is the same dentifrice further diluted with water, and the viscosity of this dentifrice is usable in the fountain tooth- 25 brush of FIG. 3 where the diameter of the passageway 38 is either one-sixteenth or one-eighth of an inch. The dentifrice tested in Example #4 is the same dentifrice further diluted with water to a very low viscosity. This dentifrice is too fluid for use with a passageway 38 of 30 one-eighth inch diameter, and the viscosity of the dentifrice forming Example #4 approaches the lower limit of viscosity which is usable in the device of FIG. 3.

The fountain toothbrush of FIG. 3 is used as follows: the base portion 10 is removed from the reservoir 20, 35 thereby exposing the brush 36 for use. The reservoir 20 is resiliently compressed to expel the dentifrice 26 through the passageway 38 into the brush 36 responsive to the internal pressure in the reservoir. When the desired quantity of dentifrice has been dispensed, the pressure ⁴⁰on the reservoir 20 is released to permit the reservoir to expand resiliently and thereby draw air through the passageway 38 up into the reservoir 20. This compression and release of the reservoir may be accomplished prior to or during use of the device, and when use of the device has been completed, the brush 36 and the neck 28 of the reservoir 20 are inserted again into the neck 18 of the base member 10 to support the device in brush-down condition until its next period of use. In this condition, the bristles 36 are ventilated by air passing through the _r(. ports 14, and air bubbles which were introduced into the reservoir 20 when it was decompressed flow upwardly under the influence of the viscosity conditions mentioned above.

With reference to FIG. 4, an alternative form of the ₅device is illustrated in which the reservoir 20 is provided with a port 40 in the upper end thereof communicating with a pocket of air 42 above the body of dentifrice 26. A blade of plastic material 44 is integrally formed with the reservoir 20 at one edge of the opening 40 and ex- θθ tends across the opening 40 to act as a check valve. The •blade 44 moves resiliently to the dotted line position illustrated at 44' to admit air directly into the upper end of the reservoir 20 when the walls of the reservoir are released after compression, and when the reservoir 20 is _(;,compressed to expel dentifrice therefrom, the blade 44 seats against the interior surfaces of the reservoir around the port 40. Preferably, the reservoir 20 and blade 40 are integrally molded at the same time and are connected during the molding operation by a thin frangible skin of plastic which renders the reservoir 20 air-tight during the shelf life when it is stored prior to sale.

With respect to the FIG. 4 embodiment of the invention, it will be appreciated that a conventional toothpaste having conventional fluidity or viscosity characteristics 75 ,243 may be employed inasmuch as it is not required that air get into reservoir 20 through the body 26 of the dentifrice.

While certain specific embodiments of the invention have been illustrated and described in detail herein, it is obvious that many modifications thereof may be made without departing from the spirit and scope of the invention.