A self-dispensing dental floss applicator that has a U-shaped elongated housing (1) with two hollow prongs (4a, 4b) set perpendicularly to the body at one end and a larger opposite end to contain the locking mechanism, the dispensing mechanism, the spool (3) of fresh floss and the spool (18 or 21) of used floss. The locking mechanism composed of a casing (5), an axle (9), two lower grip pads (17a, 17b), two upper grip pads (7a, 7b), two strip springs (8a and 8b) and a lever (6) with two eccentric friction parts is used to hold the floss in position thus creating the right tension on the floss. A tension pin (19) containing a screw (20) is provided to increase floss tension if/when needed by the user. Rotating the lever (6) up unlocks the floss. Further repeated rotations of the lever backward action the sliding mechanism containing a rack-and-pinion gear (23 and 21), together with springs 24 and 26, that in turn causes the spool of used floss (21) to rotate. Hence, new fresh floss is spanned between the prongs. In a separate embodiment, the applicator is placed on the electrical base and pressing it down will cause the spool of used floss (18) to rotate, hence pulling new fresh floss between the prongs in a very fast and easy manner. Pushing back the lever (6) to its locked position ensures the floss is tightly locked with the right tension.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International Application No. PCT/EP2008/063328, filed on Oct. 6, 2008, which claims the benefit of European Patent Application No. 07118180.4, filed on Oct. 10, 2007, the contents of both of the foregoing applications are hereby incorporated by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to tooth flossing and, more specifically, to a self-dispensing dental floss applicator usable for inserting a string or ribbon of dental floss between two single teeth and cleaning the gap between these teeth by repeatedly moving the floss back and forth and up and down.

BACKGROUND OF THE INVENTION

Dentists recognise dental flossing as a necessary and effective part of teeth cleaning and plaque removing. Flossing is indeed the only effective method for cleaning between the teeth to remove plaque build-up, which is the primary cause of gingivitis, periodontal and tooth decay. For good results, flossing should be performed daily. Beside the related applications of the applicant, today there is not any practical, well-designed device that gives consumers a high level of satisfaction with regard to usage, hygiene, etc. Finger flossing continues to be the most common method used by people even though it is primitive and does not provide good results especially for the rear teeth.

A dental floss applicator is known from EP 0 661 026 B1. According to EP 0 661 026 B1 a self-dispensing dental floss applicator is known revealing a generally U-shaped housing, having a space for a spool of floss at its one end and two hollow prongs extending parallel to each other at its other end, the floss being spanned between the free ends of the prongs and passed from the spool through a locking mechanism, a guiding section, the hollow prongs back to the guiding section and the locking mechanism wherein the locking mechanism consists of a casing, rotatably mounting a lever with double eccentric acting on two grip pads and a grip pad spring provided between said grip pads and said casing. The self-dispensing dental floss applicator known from the prior art needs the power of the fingers of the user to move the floss and is therefore less comfortable and moves the floss very slowly. Furthermore the used floss has to be cut by the user and therefore the applicator known from the prior art is less hygienic in use.

Document WO 2004/084760 A2 discloses a dental floss applicator, wherein dental floss is guided from a first spool, located in a housing, over two prongs back to the housing, where the used floss is collected on a second spool. The tension that is applied to the floss can be adjusted be the user by engaging a stop pin that stops floss from the supply spool being pulled towards the prongs and then manually turning the second spool.

Document U.S. Pat. No. 5,060,681 A discloses a dental floss applicator, wherein dental floss is guided from a first spool, located in a housing, over two prongs back to the housing, where the used floss is collected on a second spool. The tension that is applied to the floss is maintained at a constant value by means of a tapered spool and a rack and pinion locking mechanism.

Document U.S. Pat. No. 5,188,133 A discloses a dental floss applicator, wherein dental floss is guided from a first spool, located in a housing, over two prongs back to the housing, where the used floss is threaded through a locking mechanism and then further out of the housing through an exhaust channel. A fixed tension is applied to the floss by a spring-loaded locking mechanism.

SUMMARY OF THE INVENTION

It is an object of the invention to create a self-dispensing dental floss applicator mitigating the disadvantages of the prior art and being easy to handle and less expensive in production.

The above mentioned problems will be solved by a self-dispensing dental floss applicator according to claim1with a generally u-shaped housing having a space for a spool of floss at its one end and two hollow prongs at its other end, the floss being spanned between the free ends of the two prongs and passed from the spool through a locking mechanism, a guiding section, the hollow prongs back through the guiding section and the locking section, wherein the housing contains a second spool and that the first spool contains the fresh floss and that the second spool is for accumulating the used floss, wherein the second spool contains a gear wheel to drivingly connecting the gear wheel with a drive unit.

According to the invention it is advantageous that the gear wheel meshes a rack with gear teeth slidingly accommodated in a cavity of the housing.

Furthermore, it is helpful that the rack is in connection with a shaft, which can be easily operated with a lever.

According to another embodiment of the invention it is of advantage that the rack is biased by a spring, such that the spring exercises a longitudinal force along its axis pushing the rack forward. The spring is preferably a spiral spring or another type of spring.

Furthermore, it is of advantage that the shaft and the rack are connected by another spring-type element or spring element.

According to another embodiment of the invention, it is of advantage that the housing of the applicator contains an opening in the rear end of the housing allowing a driving gear wheel to be at least partly introduced through the opening to mesh the gear wheel within the housing.

Furthermore, it is of advantage that the driving gear wheel is part of a base element. According to another embodiment it is of advantage that the base element contains an electric motor, at least one battery and a switching element to start or stop the electric motor. Instead of a battery another power supply means may be provided too.

According to another inventive embodiment, it is helpful that the switching element is a micro switch being easily operated by introducing the rear end of the applicator in a recess of the base.

Furthermore, it is of advantage that the base comprises a guiding element like a positioning groove which is in operational connection with an element of the housing of the applicator.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1andFIG. 2both show different views of an inventive floss dispensing applicator. The applicator consists of a housing1, which is preferably u-shaped and made of plastic material. The housing1allows performing flossing in the most practical and user friendly way and especially with easy reach of the rear molar teeth. At the rear end of the housing there is a spool3arranged to provide fresh floss. This spool3may be removed and exchanged if the fresh floss is fully used and therefore the fresh floss spool is empty. The spool3is located in a section of the housing which is covered by the cap2. The cap2protects and holds the spool3in position.

At the front end of the housing1there are two hollow prongs4a,4barranged to provide a predetermined floss tension for flossing. The floss is fed through the prongs and kept under tension. Especially the floss is fed from the spool3through one of the prongs4a,4bto the second prong4b,4ato a used floss spool.

In the prongs are borings13a,13blocated to maintain floss in position and to keep the tension of the floss while the floss is feed through the borings13a,13b. The prongs are arranged in an angle of about 90° or less and the borings13a,13bare arranged accordingly in an angle relative to each other.

Within the housing there is a locking casing5which houses a locking mechanism of the made of a lever6an axle and grip pads7,17and springs8. The core elements are quickly removed by pulling them out of the housing1in vertical direction.

The lever6is designed as a double eccentric lever to provide locking and tension of the floss. Additionally the lever6is a dispensing actor in a mechanical version of the applicator. As can be seen inFIG. 1, the lever6is located at least partly in the housing1and consists of a part not located in the housing.

The grip pads7,17are divided in lower grip pads17a,17band upper grip pads7a,7b. The both types of grip pads are designed to exercise pressure on floss under rotation of lever6and action of spring8. The grip pads are made of metal or of plastic material. The grip pads7,17both contain saw teeth pattern.

The spring8is made of metal or of e.g. plastic material and is located below the lower grip pads. The spring8is made as curved strip spring.

The lever axle9is preferably made of metal or plastic material and keeps the lever6in a defined position and allows the lever6to turn around the axle9.

FIG. 1shows the guiding partition in the view from below situated at the top ofFIG. 1. Similarly they can be seen onFIG. 2.FIG. 4shows additionally guiding partitions10inside the housing1which can be provided in the housing ofFIG. 1or2too, but they are not seen. The guiding partitions are used to guide the floss from the fresh floss spool to the bores13or from the bores13to the used floss spool. Reference sign11denotes a bore to guide fresh floss from the locking mechanism to the bore13a, while reference sign12denotes a bore to guide used floss from the bore13to the used floss spool or to locking mechanism. As can be seen inFIG. 4, the bores11and12are almost parallel and they are located between the lever6mechanism and the prongs4. InFIG. 4the fresh floss15is shown while the used floss16is shown too. Both the fresh and the used floss are almost parallel within the housing1and the fresh floss15is spanned between the prongs4a,4bto allow the flossing. The used floss is floss already used which will be reeled on a used floss spool18or21.

The used floss spool18is located in the housing1and covered by the cap14which protects and holds the spool and gear within the housing1. The spool18contains the used floss which is reeled and the spool contains a large gear, which goes in rotary motion when the floss is dispensed in the electrical version of the applicator.

As can be seen inFIG. 4, the applicator may contain an additional tension pin19and an adjustable screw20to increase the floss tension and to provide additional floss tension.FIG. 2shows the used floss spool21with a small gear wheel which is going into rotary motion when the floss is dispensed. Additionally to the spool with the small gear wheel the applicator contains a mechanism to drive the gear wheel21. This mechanism contains a shaft22which transmits a linear movement of the shaft into a rotational movement of the gear wheel21. The shaft is therefore provided with gear teeth in linear arrangement as can be seen as rack23. In case the shaft is moved linear the gear wheel21is turned around the axis of the gear wheel. As can be seen the shaft22transmits movement of the rotating lever6to the rack23. The rack is part of the rack-and-pinion-gear device to transmit a linear movement into a rotational movement. Since the rack is moving against the force of the spring24, the spring24is able to actuate the rack23accordingly. The spring24is realised as cylindrical spring but can be realised as other type of spring if necessary. The spring provides a required pressure on rack23to push the rack back in starting position when the lever6is rotated forward to lock the floss between the grip pads7,17.

When the lever6is rotated backward the floss will be dispensed and when the lever is rotated forward the floss dispensing mechanism will be stopped.

According toFIG. 2the housing1contains a dispensing mechanism casing25, which is the rear part of the housing1of the applicator. The casing25houses the shaft22the rack23and the spring24. Therefore, the casing can be designed as having a longitudinal hollow bore containing the above mentioned parts22to24. According to another embodiment of the invention, the casing can be installed in a cavity of the housing1of the applicator, preferably before the spool21is installed in the housing1and maintained in position by cover14.

According toFIG. 2, the shaft22and the rack23are movable relative to each other. Both elements22and23have a sliding surface with which both elements can slide relatively to each other. A spring26is provided between shaft22and rack23to allow shaft22to remain in position in the casing25while the rack is free to slide. The spring may have a second function such that the spring26pushes the rack back in the upper position such that the rack frees itself from the teeth of the gearwheel18when going back in its resting position, what can be seen inFIG. 3.

The second embodiment of theFIGS. 4 and 5is provided with an electrical base27. The base27is preferably a molded plastic part including a recess for the reception of the applicator or of at least the rear end of the applicator. The base comprises an element to allow a stable positioning of the base, i.e. a socket.

As can be seen inFIG. 4, the applicator can be positioned such that the rear end of the housing1is accommodated within the base27. Within the housing there is an opening such that a gear wheel33can protrude through this opening to mesh the gear wheel18of the applicator. The gear wheel33is part of the base27.

According toFIG. 5, the base27includes a base cover28which closes the bottom of the almost semi-spherical base27. The base cover is almost flat and allows a tight closure of the base.

Preferably the closure is watertight. The cover is preferably made of plastic material. The fixation of the base cover28can be done using three screws36a,36b,36cor with other fastening means.

Within the base is an electrical motor29provided. Preferably the electric motor29is a low voltage DC-motor, e.g. a 1.5 V DC-motor. At the drive shaft of the motor29is a gear wheel provided which meshes an other gear wheel in driving connection. This double gear wheel can be seen inFIG. 5and is denoted by reference sign33. The double gear wheel allows the driving connection between the electric motor and the gear wheel18. The electric motor is connected via electrical leads with a power supply, e.g. with batteries. As power supply two batteries30a,30bare shown which are e.g. alkaline batteries of the disposable type or accordingly batteries of the rechargeable type. The batteries30a,30bmay be of 1.5 V type. According toFIG. 5the batteries30a,30bare parallel aligned and are positioned above each other. According toFIG. 5, the batteries are disposed in a battery storage room which is closed by a battery cover31, which can be of the clip-on type. This cover31protects and holds the batteries in their cavity inside the base27. To operate the electric motor a micro switch32is provided to switch the electric motor on or off. Preferably the micro switch32will be activated when the applicator is inserted in the cavity of the base and is pressed downward in the direction of the base. Accordingly the micro switch is adjusted to receive the rear part of the applicator when the applicator is inserted in the cavity of the base and switches the electric motor on.

Within the base is at least one holding part34or a holding strap which holds the elements29,32and33in place. This holding element can be a molded part of plastic material. The holding part or strap is fastened with fastening means, e.g. fastening screws35. According to the shown embodiment five screws are used to fasten and hold the strap34in position inside the base27. Furthermore, fastening means36are used to hold the base cover28in position and to fasten the base cover. According to the shown embodiment ofFIG. 5three screws are used as fastening means36.

Additionally, as can be seen inFIG. 5, a positioning groove37is provided in the base which co-operates with a positioning element of the applicator to allow the applicator to be placed properly within the base during a dispensing action.

Additionally, as can be seen inFIG. 3, an anti-return device38is provided which prevents spool18and/or21to rotate back after it has been in rotary motion to reel used floss on wheel and hence dispensed new fresh floss between the prongs. Therefore, the anti-return device is a flexible element with a teeth portion which co-operates with a teethed portion of a wheel18and/or21to allow only a rotation in one direction of the wheel.

According to the invention, the applicator allows a floss locking mechanism. The presence of two curved strip springs8a,8bplaced underneath the lower gripping pads17a,17bensures that the pressure exercised by the gripping pads7,17on the floss is almost constant independent of the floss characteristics or floss materials e.g. Nylon or Teflon, string or ribbon, waxed or non-waxed and thickness tolerances are.

Furthermore, a thin partition in the casing5of the locking mechanism between the fresh floss and used floss ensures that no direct contact exists between the two paths for fresh and used floss.

Therefore there is no direct contact between fresh floss and used floss in any part of the applicator making it extremely hygienic. Furthermore, floss spools, both fresh3and used floss18or21are located in two separate closed compartments of the applicator. There is no direct contact with any part of the human body (mouth or hand). The fact that used floss is isolated in a confined environment is a positive factor.

After each use of the applicator, the user is asked to wash the frontal part of the applicator, i.e. the prongs and the spanned floss under the tap before a new part of floss is dispensed between the prongs. This practice means used floss is relatively clean before being stored in its spool.

According to an inventive embodiment, a change in tightness of floss is possible. Should the user wants to obtain a tighter floss beyond what the mechanism already provides, he just needs to unscrew the little screw20which will receive downward pressure from the lever6when this one is in final locked position. As such, extra pressure will be exercised on the used floss string16from pin19as it passes through it.

The introduction of the dual function of the lever in the mechanical version of the self-dispensing dental floss applicator is generally favourable. The mechanical version of the inventive self-dispensing dental floss applicator according toFIGS. 1 to 3relies on finger power to obtain floss dispensing. It is a lower cost and slower version of the electrical model described according toFIGS. 4 and 5yet it performs the same function. The double eccentric lever6continues to play a floss locking role.

For ease of use, the action to lock the floss is by pressing forward lever6with the thumb and unlock by pulling it backward with the index finger. When the lever6reaches almost 45 degrees forward, the fresh floss is locked between the gripping pads7aand17awhile the used floss will be locked completely between the gripping pads7b,17bas the lever6is pressed down completely. The added feature of the extra tension pin19allows creating more tension on the floss if/when required by the user.

The lever plays also the added role of floss dispenser. By pulling the lever6backward with the index finger, a shaft22in the sliding mechanism is moved backward and the rack-and-pinion gear system23and21generates a rotary motion of the used floss spool21. Hence, the used floss16is pulled away from the prongs4aand4bat the end of the applicator. The user just needs to action the lever backward a few times to get a new part of fresh floss to be spanned between the prongs of the applicator. The lever is brought back to its neutral position thanks to spring24and spring/pin26in the sliding mechanism. It has to be noted that spring strength of spring24is far stronger than spring26. Device26allows shaft22to slide away from rack23which in turn moves up and disengages itself from the teeth of gearwheel21before reaching its resting position The used floss spool21can only rotate in one direction as a small blocking mechanism38prevents it from unreeling.FIGS. 4 and 5show a fully electrical self-dispensing floss applicator according to a second embodiment of the present invention to provide ultimate user-friendliness and easy dispensing of floss. The inventive applicator is a combination of a light ergonomic applicator and a stable compact electrical base. In order to fully control the movement of floss between teeth and avoid hurting gums, it is critical that the applicator be as light, user-friendly and ergonomic as possible.

The incorporation of an electrical motor, a gear box and a set of batteries in the applicator itself would create a heavy, unbalanced and bulky applicator. Such characteristics would make it very difficult and almost impractical for the user to floss safely and effectively.

The electrically driven applicator ofFIGS. 4 and 5has essentially a similar design as the mechanical version described above according toFIGS. 1 to 3. The main difference is that lever6needs only to perform the locking function and, as such the sliding dispensing mechanism is not needed. The used floss reel18incorporates a large gearwheel that allows it to be set in rotary motion from outside the casing.

FIG. 6shows details of the locking mechanism of the inventive dental floss applicator in different sectional views. Sectional view mm shows the lever6in an open position, perpendicular to the housing1, where both fresh floss15and used floss16are free to move such that floss dispensing is performed. The free movement of the floss is possible since the both elements7a,17aincluding the saw-teeth have a certain distance such that the floss is free to move.

Sectional view nn and sectional view oo show the lever in a 45 degree position where fresh floss15is locked (sectional view nn), while the used floss16is being tensioned (sectional view oo) by the dispensing mechanism.

Sectional view p and sectional view rr show the lever6in the final locked position, alligned with housing1. The sections pp and rr show fresh floss15and used floss16totally locked under pressure exercised by lever6on grid pads7aand7band by springs8aand8bon grip pads17aand17brespectively.

A compact base27contains the electrical motor, the gearbox and the set of two e.g. AA batteries. By holding vertically and pressing down the unlocked applicator in the cavity located at the top of the base27, a small micro switch32activates the electrical motor, which in turn sets the double gearwheel33in rotary motion. A positioning groove37that receives shape38ensures the applicator is placed properly on the base. The used floss spool18in the applicator is set in rotary motion and the flossed is dispensed rapidly. The user just needs to press the lever6forward in locked position while the floss is dispensed electrically by the base. The key feature here is the speed and ease at which dispensing of floss is made. Here again, the extra tautness feature19exists according to one inventive embodiment. The applicator is ready for use.

One of the great advantages of such design is that a family does not need as many electrical bases as they need applicators. One base per bathroom is enough as it can be used by many applicators. Additionally, 1.5 Volt AA batteries can be of a disposable or rechargeable nature. The base is compact enough to accompany the user during trips away from home. The base also plays the role of applicator stand when not in use.

The invention relates to a self-dispensing dental floss applicator that has a U-shaped elongated housing1with two hollow prongs4a,4bset perpendicularly to the body at one end and a larger opposite end to contain the locking mechanism, the dispensing mechanism, the spool3of fresh floss and the spool18and/or21of used floss. The locking mechanism composed of a casing5, an axle9, two lower grip pads17a,17b, two upper grip pads7a,7b, two strip springs8a,8band a lever6with two eccentric friction parts is used to hold the floss in position thus creating the right tension on the floss. According to an embodiment of the invention, a tension pin19containing a screw20is provided to increase floss tension if/when needed by the user. Rotating the lever6up unlocks the floss. Further repeated rotations of the lever backward action the sliding mechanism containing a rack-and-pinion gear23,21, together with springs24,26, that in turn causes the spool of used floss21to rotate. Hence, new fresh floss is spanned between the prongs. In a separate embodiment, the applicator is placed on the electrical base and pressing it down will cause the spool of used floss18to rotate, hence pulling new fresh floss between the prongs in a very fast and easy manner. Pushing back the lever6to its locked position ensures the floss is tightly locked with the right tension.FIG. 7shows a third embodiment of the present invention, which differs from the first embodiment shown inFIGS. 1 to 3in that the used floss spool21is provided with a cogged part23awhich acts as a clutch. Thus, the gear wheel of the used floss spool21can remain in constant engagement with the toothed rack23during the forward and backward movement of the lever6, as the clutch ensures that the used floss spool21only turns in the direction in which used floss is wound up onto the spool.

A helical spring39creates the required pressure on the clutch gear wheel21,23aso that rotational movement is transmitted to the spool21in order to wind up used floss and so that the cogged part23ais released when the piston22returns to its resting position under pressure of the spring24. A retention pin26aprevents the piston22from moving out of the dispensing mechanism casing25during its linear motion.

FIG. 8shows a fourth embodiment of the present invention. In this embodiment, the backwards and forwards motion of the lever6is converted into rotational motion of the used floss spool21aby means of a crankshaft arrangement, comprising a piston40, a crankshaft42, a connecting rod41, a helical spring43, a wire spring44and a retainer pin45. The piston40is coupled to the connecting rod41via an axle pin47and the connecting rod41is coupled to the crankshaft42via an axle pin46. The crankshaft42is formed integral with the used floss spool21a.

Under backward movement of the lever6, piston40transforms its linear movement into rotational movement of the crankshaft42via the connecting rod41. As the crankshaft42completes the first half turn, the retainer pin45compresses the helical spring43, which provides the necessary force to return the piston40to its original position once the lever6is back in the “locked” position. At the same time, the wire spring44provides the necessary force to push back the connecting rod41to its original position so that the used floss spool21arotates through 360 degrees.

FIG. 9shows a fifth embodiment of the present invention. In this embodiment, the backward and forward motion of the lever6is converted into rotational motion of the used floss spool21bby means of a helical piston54and a conical gearwheel52.

All elements of the dispensing mechanism, comprising the helical piston54, a connecting rod53, the conical gear wheel52and a helical spring51are housed in a casing50. The casing50is placed in a specially designed rectangular cavity in housing1before the used floss spool21is placed in housing1and maintained in position by cover14. The conical gear wheel52is engaged with a conical gear wheel of the used floss spool21band is mounted on the connecting rod53.

Under backward movement of lever6, helical piston54is set into helical motion, which is converted into a rotational motion of the conical gear wheel52via the square section of connecting axle rod53passing through the conical gear wheel52. Rotational motion of the conical gear wheel52is transmitted to the used floss spool21bvia the engagement of the conical gear wheels. After floss is dispensed, the helical spring51pushes against a stopper washer55mounted on the connecting rod53and thus provides the necessary force to push connecting rod53and piston back to their original positions when the lever6is back in the “locked” position.

The cogged end of connecting rod53, as shown in the top part ofFIG. 9, is designed to allow rod53to move back without rotation as the used floss spool21bis prevented from unreeling by the anti-return device38.

REFERENCES