Cartridge for liquid or pasty dentifrice

Abstract

A cartridge for liquid or pasty dentifrice is described which is adapted for use in a fountain toothbrush having a bristle carrier, a guiding sleeve member connected to the latter for receiving the cartridge therein and serving as a handle of the toothbrush, duct means leading from the bottom part of the sleeve member through the bristle carrier to a set of bristles on the latter, an actuating means with which the cartridge is adapted to be brought into engagement, which actuating means comprise a piston borne by the bristle carrier at its end away from the bristles, which cartridge is hermetically closed at the end thereof destined for facing away from the bristle carrier, and has a reservoir for dentrifice in its interior and an outlet passage of the latter reservoir opening in that frontal face of the cartridge which is destined to face the bristle carrier; the outlet passage is adapted for receiving therein the said piston in displaceable, sealing engagement; furthermore, the cartridge comprises a sealing membrane hermetically closing off the said outlet passage prior to introduction of the cartridge into the sleeve member, and the membrane is removable by piercing means associated with the piston, at the time of the aforesaid introduction of the piston into the said outlet means.

Description

BACKGROUND OF THE INVENTION

This invention relates to a cartridge for liquid or pasty dentifrice, which cartridge is adapted for use in a fountain toothbrush having a bristle carrier and, connected to the latter, a preferably rigid-walled guiding sleeve member serving as a handle and destined for receiving the cartridge therein, the said bristle carrier having a duct leading from the bottom part of the sleeve member through the bristle carrier to the bristles on the latter, as well as actuating means which the cartridge is adapted to engage, which actuating means comprise a piston borne by the bristle carrier at its end remote from the bristles.

A fountain toothbrush of this kind has been described in U.S. Pat. application No. 453,391 (Case 261/267) filed on the same day as the instant application. Such fountain toothbrushes may be equipped with a refillable dentifrice reservoir in which case the wall of the reservoir will constitute itself the handle of its toothbrush. As has been mentioned, the wall of the handle should preferably be rigid, at least to a sufficient degree so as not to yield to manual pressure by the fingers of the holder.

Due to the fact that most of the time a fountain toothbrush will be carried by the user clipped in a pocket with the rear end of the toothbrush pointing downwardly, sealing means are required which must be particularly safe and are accordingly complicated and costly.

The problems of mounting such actuating means with perfect seal in the rear end wall of the reservoir, away from the bristles, are completely avoided in the fountain toothbrush described in the above-mentioned patent application No. 453,391 while, at the same time, the expense for separate actuating means is eliminated.

Preferably, the fountain toothbrush of the intially described type is provided with arresting means preventing a complete withdrawal of the piston out of engagement with the reservoir during normal use of the toothbrush.

It has been found that, surprisingly, a relative short stroke of the piston into the reservoir is sufficient to convey a small portion of a dentifrice of satisfactory liquidity onto the bristles, even when only a minor portion of the internal volume of the reservoir remains filled with the dentifrice. When, however, dispensing toothpastes of conventional consistency, it is necessary to plunge the piston more or less deeply into the interior of the reservoir, depending on the amount of dentifrice present in the latter.

Fountain toothbrushes which have a movable piston in the dentifrice reservoir have been described, for instance in U.S. Pat. Nos. 2,214,144, 2,305,158 and 3,039,476 as well as in French Pat. No. 769,734. However, in all these devices, the piston must be actuated from the rear end of the reservoir by means of an actuating means passing through the end wall of the reservoir.

The problems of sealing such actuating means in the reservoir wall are completely avoided in the fountain toothbrush of the initially described type while, at the same time, the expense for separate actuating means is eliminated.

Apart from the discharge opening destined for receiving the piston for displacement therein, the rigid reservoir wall has no further opening.

OBJECT AND SUMMARY OF THE INVENTION

It is an object of the present invention to provide a reservoir for use with the type of fountain toothbrush initially described.

This object is attained by an exchangeable cartridge according to the invention, to be filled or being filled with dentifrice, which cartridge has a single discharge opening being sealed, prior to insertion into the lastmentioned fountain toothbrush, by means of a sealing membrane which can be removed or perforated during the insertion of the cartridge into the guiding sleeve member and before or during introduction of the piston into the discharge opening of the cartridge. Preferably, the cartridge will protrude with its closed rear end portion from the open rear end of the sleeve member serving as a handle for the toothbrush.

As has been mentioned before, when a dentifrice of suficiently low viscosity is used, a short inward displacement of the piston into the cartridge will be sufficient to convey an adequate amount of dentifrice to the bristles, even when the degree of filling in the cartridge is low.

At least part of the duct leading through the bristle carrier should preferably be formed as a capillary tube, thus preventing the liquid dentifrice to pass through to the bristles while the piston is in its most withdrawn end position relative to the front end of the reservoir facing toward the bristle carrier.

When using a liquid dentifrice of conventional viscosity, the capillary tube preferably has a diameter of about 0.5 to 1.5 mm, whereas the remaining portion of the duct can have a diameter above 1.5 mm and preferably one of about 2 mm. Very satisfactory results were obtained with a duct 2 mm in diameter, over most if its length whereof only the opening towards the set of bristles showed a capillary width of 0.8 mm and Weleda mouth-water or Chlorodont mouth-water of a commercially available composition were used.

Cap means for sealing can be provided especially for use under extreme conditions, e.g. when the toothbrush is taken along in aeroplanes, flying through the stratosphere, or when using dentifrice liable to be decomposed by air. Such cap means close the mouth of the duct from the piston into the reservoir while the piston is in neutral postion. Elastic sealing means are preferred for this purpose which may be formed as a projection of the inner wall of the handle surrounding the reservoir, whereby said means preferably lock the duct leading out of the side of a projection of the piston into the reservoir, while the piston is in the above-mentioned maximally withdrawn end position. Abutment means determining the inward displacement of the piston relative to the reservoir in the handle are preferably formed by a projection on the piston or on the bristle carrier carrying the same, which projection protrudes through a cut-out in the adjacent wall of the handle. These abutment means can be manipulated by a finger, i.e. the index finger, of the same hand that holds the handle. In this case, an inward displacement of the piston from the above-described end-position of only 2 mm into the reservoir is sufficient, when using liquid dentifrice of conventional viscosity.

In order to be well adapted for use in the initially described fountain toothbrush, the cartridge according to the invention is hermetically closed at its rear end, i.e. at its end away from the bristle carrier while in its frontal end wall destined to face the bristle carrier, the cartridge has an outlet opening of the dentifrice reservoir located in its interior, into which outlet opening the piston mentioned hereinbefore must be sealingly inserted, a sealing membrane which closes a discharge opening during storage prior to use being adapted for perforation by a thorn member or the like perforating means associated with the piston.

When inserting the piston in the discharge orifice, the thorn member first perforates the sealing membrane of the cartridge and as the piston is advanced further in the discharge orifice in the direction toward the interior of the cartridge, dentifrice is conveyed from the cartridge by way of passage means associated with the piston and further through the duct through the bristle carrier to the bristles.

Preferably, the wall of the cartridge bears abutment means for a resetting member associated with the bristle carrier and serving to return the cartridge, after actuation, as described above, to its initial postion wherein no flow of dentifrice to the bristles occurs. These abutment means may comprise, for instance, a recess in the above-mentioned frontal end wall of the cartridge and adapted for receiving therein one end of a resetting spring.

Preferably, abutment means for limiting a displacement of the cartridge inside the sleeve member are provided on the outside wall of the cartridge, which abutment means engage corresponding abutment means on the bristle carrier.

In order to facilitate manufacture of the cartridge from thermoplastic resin material by injection molding processes requiring only simple tools, it is preferred to produce the cartridge with an open rear end and then to close the rear opening by means of a lid member which can be welded, e.g. by ultrasound, thereon to provide a hermetic seal, after the cartridge is filled.

The cartridge may be of approximately rectangular or circular or horseshoe-shaped cross-sectional area, the latter being preferably adapted to fit snugly, but well displaceably, into the internal cross-sectional area of the sleeve member on the bristle carrier. In case the guiding sleeve member is of correspondingly somewhat larger, horseshoe-shaped cross-section and in case the narrow flat side of the horseshoe defines a face of the wall of the sleeve member located on the side of the bristle carrier opposite that bearing the bristles, then the guiding sleeve member will constitute a handle which is particularly comfortable and safe to grasp by the hand of the user when brushing his teeth with the initially described fountain toothbrush.

The invention will be better understood, and further objects and advantages will become apparent from the ensuing detailed specification of preferred but merely exemplary embodiments taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows in axial sectional view a first embodiment of the cartridge according to the invention inserted into a fountain toothbrush adapted for receiving the cartridge and having a guiding sleeve member therefore, which sleeve member is fastened on the bristle carrier of the toothbrush and serves as the handle of the same;

FIG. 2 is a cross-sectional view of the same embodiment of the cartridge as well as of the sleeve member surrounding the same seen in a plane indicated by II--II in FIG. 1;

FIG. 3 shows an embodiment of the cartridge according to the invention similar to that shown in FIGS. 1 and 2, but in perspective view; and

FIG. 4 shows an embodiment of the combination of the cartridge and toothbrush with a cap thereon.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The fountain toothbrush shown in FIGS. 1 and 2 comprises as main parts a bristle carrier 33 which bears at its forward end a set of bristles 4 while about its rearward end face 33a, remote from the bristle bearing front end, there is provided an elongation in the form of a rigid walled sleeve member 31 which is open at its rearward end and which serves as the handle of the toothbrush. A cartridge 30 containing liquid or pasty dentifrice has been inserted through this open sleeve end. From the rearward end face 33a of the bristle carrier 33 a duct 12 extends toward the bristle-bearing end of bristle carrier 33 and opens through a lateral outlet duct 19 between the bristles 4. The cross-sectional area of this outlet duct 19 is so dimensioned that an adequate capillary action is exercised on the dentifrice as a function of the viscosity of the latter. Thereby, dentifrice is prevented from flowing out of the discharge orifice of duct 19 when the toothbrush is not actuated, even while the toothbrush is held with its bristles downward and is shaken or waved to and fro.

Duct 12 opens via enlarged end portion 38 in the end face 33a of bristle carrier 33, and a piston 37 is force fit into the enlarged duct portion 38. Piston 37 has an axial passage 32 therethrough. The dentifrice-filled cartridge 30 which is inserted in the sleeve member 31 has in its front face 30b which faces toward the bottom of the interior of sleeve member 31, a discharge passage which is in free communication with the interior 30d of cartridge 30, which passage 34 is so located in the inwardly directed front face 30b of cartridge 30 and which is of course of such diameter that piston 37 will enter passage 34 and will be engaged sealingly displaceably in passage 34 during introduction of cartridge 30 into sleeve member 31. Prior to this insertion into sleeve member 31, the filled cartridge 30 is hermetically sealed by means of a thin membrane 30e. On the outside wall of cartridge 30 there is provided a nose 30c of somewhat resilient material which can be brought into snap engagement with a groove or window 31a in the wall of sleeve member 31. Abutment of nose 30c against the end wall of groove or window 31a situated in axial forward direction, i.e. toward the bristles 4 limits the inward movement of cartridge 30, in the same direction.

Recesses 33b and 35, provided respectively in the rearward end face 33a of bristle carrier 33, in the interior of sleeve member 31, on the one hand and in the opposite frontal face 30b of cartridge 30, facing toward the bristles 4, on the other hand, are aligned with one another and receive each one end of a compression spring 36 which serves as resetting spring. The displacement of cartridge 30, caused by this spring 36, in outward direction relative to the rearward open end of sleeve member 31, is limited by nose 30c of cartridge 30 abutting against the rearward end wall of groove or window 31a. This will also prevent cartridge 30 from becoming separated unintentionally from sleeve member 31. However, if a stronger pull is exerted on the rear end of cartridge 30, which protrudes from the open rearward end of rearward sleeve 31, the somewhat resilient nose 30c will be disengaged from groove or window 31a, and an empty cartridge can thus be removed from sleeve member 31 to be replaced by a new, full cartridge. Instead of having nose 30c made of resilient material, it is also possible to make the wall of cartridge 30, in particular in the vicinity of nose 30c, of somewhat resilient material. When a window 31a is provided as shown in FIG. 1, it is possible to urge nose 30c inwardly, e.g. with the nail of a finger, and simultaneously move the nose 30c slightly outwardly relative to sleeve member 31, thereby disengaging nose 33 from window 31a, whereby cartridge 30 can be easily drawn out of sleeve member 31. For the same purpose, window 30a may also be arranged nearer the forward end, e.g. in the middle zone of sleeve member 31. A thorn 39, protruding from the frontal face of piston 37 facing toward reservoir 30d, which thorn surrounds passage 32 through the piston, will perforate the membrane 30e of cartridge 30, when the latter is pushed sufficiently far into sleeve member 31. Preferably, this will occur shortly before, or simultaneously with nose 30c entering into snap engagement with the groove or window 31a.

In the positions of cartridge 30, sleeve member 31, piston 37 and spring 36 as shown in FIG. 1, the fountain toothbrush is in non-actuated condition. When using the same, a protective cap (not shown) is removed from the toothbrush, and the latter is held in the hollow of one hand with the end thereof bearing bristles 4 protruding out of the plam of the hand past the little finger. The thumb of the same hand thus comes to rest on the rearward end of the cartridge at 30a. By briefly pressing the thumb downward, cartridge 30 is moved into sleeve member 31 until nose 30c abuts against the forward end wall of groove or window 31a. Thereby, a small amount of dentifrice is caused to flow out of reservoir 30d and is conveyed via piston passage 32, duct 12 of the bristle carrier, and the capillary outlet duct 19 to the bristles 4 and spreads on the latter.

This dispensing of dentifrice takes place partically independently of the degree of filling of reservoir 30d. When nose 30c abuts against the forward end wall of groove or window 31a, the thumb can release at once the rear end of cartridge 30, and resetting spring 36 will push cartridge 30 back into its starting position.

The embodiment of a cartridge 40 shown in perspective view in FIG. 3, is of horseshoe-shaped cross section. Reservoir 40d in the interior of cartridge 40 has a discharge outlet via a passage 44 in the cartridge frontal face 40b to be inserted facing toward the bristles 4. Moreover, a recess 45 is provided in frontal face 40b, which recess serves for receiving therein one end of the resetting spring 35 (shown in FIG. 1).

The dash-dotted line I--I indicates the plane in which this cartridge 40 has practically the same sectional view as shown in FIG. 1. However, the nose 40c is provided on the opposite side of the cartridge as compared with nose 30c shown in FIG. 1. Correspondingly, the groove or window in sleeve member 31, into which nose 40c is to enter into snap engagement, must be located on the opposite side of sleeve member 31 nearer to the connection of the latter to the bristle carrier 33.

The mass production of the cartridges shown in FIGS. 1 to 3, from thermoplastic resin materials by modern injection molding techniques is carried out most conveniently by making the cartridge with its rear end open, but having the sealing membrane 30e, 40e produced integral with the remainder of the cartridge wall, and closing the cartridge, after filling in the dentifrice, by means of a lid 30a, 40a being made preferably of the same material as the remainder of the cartridge and sealing the lid hermetically, preferably by ultrasonic welding, onto the remaining wall of the cartridge, without affecting the quality of the dentifrice in the cartridge.

Claims

what is claimed is:

1. A cartridge for liquid or pasty dentifrice, combined with a fountain toothbrush having a bristle carrier, a guiding sleeve member connected to the latter for receiving the cartridge therein and serving as a handle of the toothbrush, a duct means leading from the bottom part of the sleeve member through the bristle carrier to a set of bristles on the latter, an actuating means with which the cartridge is adapted to be brought into engagement, said actuating means comprising a piston borne by the bristle carrier at its end away from the bristles, which cartridge is hermetically closed at the end thereof destined for facing away from said bristle carrier, and has a reservoir for dentifrice in its interior and an outlet passage of said reservoir opening in the frontal face of said cartridge being destined to face said bristle carrier, said outlet passage being adapted for receiving therein said piston in displaceable, sealing engagement, said cartridge comprising a sealing membrane hermetically closing off said outlet passage prior to introduction of said cartridge into said sleeve member, said membrane being ruptured by piercing means associated with said piston, at the time of the aforesaid introduction, and abutment means provided in the wall of said cartridge comprising a recess in the frontal face of said cartridge and adapted for receiving therein a resetting spring.

2. The combination as described in claim 1, wherein said cartridge further comprises on the outer wall thereof, stop means adapted for limiting displacement of the cartridge relative to said guiding sleeve member in a direction toward and away from said bristle carrier, said stop means being engageable by corresponding stop means on said bristle carrier or on said sleeve member.

3. The combination as described in claim 1, having a wall being open at the end destined for facing away from said bristle carrier, and a lid member hermetically closing said open wall end.

4. The combination as described in claim 1, being of approximately rectangular cross section.

5. The combination as described in claim 1, being of horseshoe-shaped cross section.

6. A cartridge usable in the combination as described in claim 1, comprising a reservoir for dentifrice in its interior and an outlet passage of said reservoir opening in a frontal face of said cartridge, a sealing membrane hermetically closing off said outlet passage prior to use of said cartridge in said combination, and abutment means provided in the wall of said cartridge comprising a recess in the frontal face of said cartridge and adapted for receiving therein a resetting spring.