EP0910259A1

EP0910259A1 - Dental hygiene device with replaceable cleaning part

Info

Publication number: EP0910259A1
Application number: EP97930373A
Authority: EP
Inventors: Georg Weihrauch
Original assignee: Coronet Werke GmbH
Current assignee: Coronet Werke GmbH
Priority date: 1996-06-22
Filing date: 1997-06-19
Publication date: 1999-04-28
Anticipated expiration: 2017-06-19
Also published as: BR9709935A; TW392457U; PL330722A1; CA2258096A1; TR199802645T2; SK281757B6; BR9709936A; AU3261697A; RO115775B1; ID19309A; HUP9902958A2; WO1997049314A1; DE19624962A1; RU2171084C2; AR007434A1; CN1105529C; RU2171085C2; ATE191832T1; JP2000513957A; ID17155A

Abstract

The invention relates to a dental hygiene device, for example a toothbrush, with a handle, a head and a cleaning part which can be inserted to lock in a hollow thereof, said cleaning part being ejectable by a resilient pressure member arranged on the back of the head and acting on the rear side of the cleaning part by pressurisation. To achieve a tight seal on said rear and to manipulate in a simple manner, the invention provides for the head to have a rear opening which is closed by the pressure member and into which the cleaning part engages, and the pressure member to be in the form of a flexible, plastic disc and the peripheral edge thereof to be fixed to the wall of the opening to form a seal.

Description

Dental care device with exchangeable care part

The invention relates to a dental care device with a handle, a head and a care part which can be latched in a recess of the same, which can be ejected by means of a resilient pressure piece arranged on the back of the head, which acts on the back of the care part when pressure is applied.

Dental care devices of the aforementioned type are particularly common as toothbrushes, which is why only these are discussed below. Equally, this includes devices that are used exclusively for massage of the gums or for the care of the interdental spaces.

Toothbrushes are needed far more often than all other types of brushes. The reason is the frequent use for proper dental care (up to three times a day) and the resulting rapid Wear. In addition, the toothbrush should be replaced even with relatively little wear, which would be acceptable with other brushes, in order to always ensure optimal effectiveness.

Due to the high consumption of toothbrushes - in Germany approx. 150 million - there is an increasing question of disposal and resource conservation, since the mass fraction that is unusable due to wear is extraordinarily low compared to the total mass and the total mass to be disposed of even with one hundred percent recycling can no longer be worked up to the same product, since the recovered material no longer meets the high quality requirements that are indispensable, for example, for the bristle material of a toothbrush. Even if the known brushes with interchangeable brush parts would basically allow only the brush part to be exchanged after being closed, this environmental problem has not previously been the focus, on the one hand, but it also plays with conventional brushes, such as cleaning brushes, body brushes, etc. , a comparatively minor role, since the period of use is much longer and the mass ratio of useless and still usable material is not as disproportionate as that of toothbrushes.

Finally, the special feature of toothbrushes should be noted that they must be usable as intended by people of all ages and all levels of education, so that the brush part can be replaced in the simplest way and with little effort and with a sufficiently secure connection of the parts got to. There are essentially two systems on the market today. In the so-called interchangeable head brushes (EP 0 199 849 B1, DE 94 20 405 UI), the entire head with the bristles is detachably attached to the handle or handle. The latching fastening means are arranged essentially transversely to the longitudinal axis of the handle on this and on an attachment of the head and are brought into engagement by plugging the head and handle together in the direction of the longitudinal axis. Conversely, both parts can be released by pulling them apart in the longitudinal axis. These interchangeable head brushes are satisfactory in terms of use and hygiene. However, the amount of plastic in the head that becomes waste after the bristles wear out is still very high. In addition, there is the disadvantage that the fastening means lie in the transition area between the head and the stem, that is to say in a zone in which the greatest bending forces act when in use. It is precisely in this zone that the toothbrush is weakened by the design measures for the fasteners. This is particularly serious because, for technical reasons, a slim and possibly resilient neck is desired between the handle and the head, which practically cannot be achieved with such interchangeable head brushes. Interchangeable head brushes have therefore already been proposed in which the head is locked with the slim neck on the thicker handle. Although the technical advantage is largely retained, this is at the expense of an even greater amount of plastic waste. In addition, with all interchangeable head brushes there is the danger that, if the catch is not properly locked or if the catch fails during use, serious injuries may occur in the oral cavity. In the other known system to which the dental care device belongs, the bristles are fastened to a carrier in the form of a thin plate and this brush part is interchangeably locked in the frame-like housing-like head (DE 44 34 617 AI). The carrier has tab-like catches on its circumferential surface and the housing has corresponding groove-like depressions. Furthermore, the back of the carrier has a pin which engages in a hole in the bottom of the housing and forms an exposed pressure surface on the back of the head. The carrier is snapped into the head and can be ejected by pressing on the pin. The plastic mass to be exchanged when the bristles wear out is reduced to a minimum and the replaceable brush parts can be produced inexpensively due to the low use of materials. Compared to interchangeable head brushes, however, there are hygienic and also constructive problems. Dirt accumulates on the one hand in the gap between the carrier and the housing cheek which inevitably dries out, and on the other hand bacteria nest. This applies more or less to the entire gap between the head and the wearer.

The carrier has therefore already been provided with a circumferential elastic edge on its bristle side (DE 37 24640 C2), the back of which should lie tight against the end face of the housing cheek. This presupposes corresponding tensile forces that pull the carrier into the housing, and thus correspondingly large ones

Locking forces. This in turn complicates the insertion and ejection of the brush part. Since the locking takes place by positive locking, the locking means must be correspondingly large-volume, which requires large wall thicknesses on the head. different. Even more complex is an embodiment (DE 29600 398 UI) in which elastic flat seals are inserted on all sealing surfaces between the carrier and the housing, which at the same time hold the brush part by means of a correspondingly high preload. The pretension must be completely absorbed by the housing cheek, which inevitably widens after a short time and no longer guarantees a secure hold of the brush part.

Other proposals (DE 91 09 625 UI, DE 34 34 617 AI) to provide the locking strips only in sections on the circumference of the carrier are inevitably at the expense of the tightness of the gap, since the locking strips and recesses lie in the sealing surfaces and very tight tolerances are observed must, on the one hand, to ensure that the sealing surfaces fit snugly, and on the other hand to ensure that they engage securely. Such tolerances can hardly be realized with injection molded parts and with the inexpensive plastics that are only suitable for the head and the handle. In addition, the housing cheek stands by the

Latching forces constantly under elastic pretension. Since plastics are not creep-resistant under tension (cold flow), the tension of the housing cheek decreases very quickly, so that the handle and head only have a limited service life. Since the fatigue of the plastic and the associated increase in tolerances cannot be perceived by the user, he may not notice the failure of the locking means until he brushes his teeth. If the brush part comes loose during use, it can in turn lead to unpleasant injuries in the mouth and on the gingiva.

A very stable and permanent connection between the brush part and the head results in a known toothbrush (DE 41 04 314 AI) in that at the back of the

Carrier two V-shaped strips are formed, which run over the entire length of the carrier. These engage in a corresponding V-shaped opening on the head, which also runs in the longitudinal axis over the entire length. When inserting, the strips must be deformed inwards and towards each other to such an extent that they can pass through the narrowest cross section of the V-shaped slot in order to then spread out in the slot. The elastically deformed parts of the locking connections are therefore on the interchangeable part, where the material fatigue is less significant. The forming forces on the strips, which are necessary for establishing and releasing the latching connection, are, however, so great that the brush part can only be pressed in or levered out with the aid of specially adapted tools. The need for such special tools not only leads to correspondingly high system costs for the consumer, but also stands in the way of practical implementation of the system on the market. This also applies because a requirement essential to avoid injuries, namely a smooth shape of the brush back, has not been met. Finally, this toothbrush is also completely unsuitable for hygienic reasons, because the slot and the strips form several cracks in which dirt and remnants of dentifrice are deposited and bacteria nest. The same applies to another known embodiment (US Pat. No. 4,543,679) with a spreader pin on the carrier which engages in a V-shaped through-hole on the back of the head.

In all versions with a peg exposed on the back as a pressure piece, the problem of the penetration of dirt and the Nesting of bacteria. In addition, the back of the head is not smooth and gaps and indentations can increase with increasing use. The irregularities on the surface of the back can lead to injuries in the oral cavity.

The abovementioned disadvantages are largely eliminated in the embodiment already indicated (DE 37 24 640 C2) by the housing being closed on the rear and the wall thickness of the bottom of the housing along a closed line similar to a so-called film Hinge is weakened, so that the area of the base lying within the line of weakness is connected to the remaining area of the base via a spring-like connection. The pressure piece thus obtained can be displaced with the finger when pressure is applied and act directly on the carrier in order to eject the care part. This embodiment has the further advantage that the manufacturing tolerances for the locking means can be chosen closely regardless of the ejection function of the pressure piece. The disadvantage, however, is that this embodiment inevitably allows only a small stroke on the pressure piece. Furthermore, the head must consist of a comparatively high quality plastic to ensure the spring properties for the pressure piece. Finally, fatigue fractures can easily occur in the area of the spring-like connection of pressure piece and base. Since the spring linkage inevitably requires gaps on the back of the head that weaken the wall thickness, the hygienic requirements are also poorly met here and injuries to the mouth can also occur here.

The invention has for its object a dental care device of the latter structure to be trained so that the special hygienic requirements are met and the performance characteristics are improved.

This object is achieved in that the head on the back has an opening, which is closed by the pressure piece, into which the care part engages, and in that the pressure piece is designed as a flexible disk made of plastic and is sealingly fixed with its peripheral edge to the wall of the opening .

The embodiment according to the invention essentially consists of three parts, namely the head, which is optionally equipped with a handle, the care part inserted into a trough of the head, which at least partially engages in the opening of the head, and the separate pressure piece, the as resilient plastic disc is formed and is sealingly attached to the edge of the wall of the opening.

In this version, the manufacturing tolerances for the snap connection of the care part and head are independent of the eject function of the pressure piece. The structural design of the locking connection can therefore be based exclusively on the intended use, namely locking and unlocking. The type of attachment of the pressure piece to the wall of the opening, as well as the material of the pressure piece, can only be selected with a view to the intended use. Since the elasticity required for ejection is achieved solely in the structural design of the disk, the housing forming the head does not suffer any weakening and the stroke of the pressure piece in particular can be functionally optimized. Finally, the opening hermetically sealed in the head, so that a smooth surface is presented. In addition, gaps open to the outside with their hygienic problems are avoided.

The stroke of the pressure piece and its spring behavior when ejected can be optimized in terms of use technology in such a way that the function is sensitive or acoustically perceptible to the user, these effects possibly also by appropriate design of those separated from the function of the pressure piece Snap connection can be supported.

In a preferred embodiment it is provided that the care part has a pin on its rear side located in the recess of the head which extends into the opening up to the

Disc engages, wherein the pin is preferably guided in the opening.

This results in a play-free arrangement of the care part in the head and in particular the insertion of the care part in the head is facilitated by the guidance of the pin. The pin on the care part and the opening on the head can be provided in an optimal position for both insertion and ejection.

In a further advantageous embodiment it is provided that the disc is flush with the surface of the back on the head and is curved toward the outside towards its center.

Due to the arching, it is possible to create a "click effect" during the ejection process, which strikes the intended goal, namely the detachment of the care part from the head. lig. Even for the visually impaired, the pressure piece can be easily identified as sensitive.

The disk can be made of a different plastic than the head, in order to again optimize the function of the pressure piece in terms of material. In addition, the disc can be visually lifted off the head to visualize the function of the pressure piece.

The disc is preferably made of an elastomer which, on the one hand, permanently ensures the function as a pressure piece, on the other hand offers a certain grip when ejected and finally avoids injuries in the oral cavity.

The disc can be inserted into the opening of the head in a form-fitting or non-positive manner, or it can also be injected on the occasion of the injection molding of the head using the in-mold method.

The invention is described below with reference to two exemplary embodiments shown in the drawing. The drawing shows:

1 shows a longitudinal section through the head of a broken toothbrush;

Figure 2 shows a section II-II of Figure 1;

Figure 3 shows a section III-III according to Figure 1 and

FIG. 4 one corresponding to FIG. 3 Section of another embodiment of the head of a toothbrush.

The exemplary embodiments shown in the drawing are a dental care device in the form of a toothbrush, of which only the head 1 is shown in the drawing. This can be followed by a conventional handle on the right-hand side in FIG. 1, which is injection-molded in one piece with the head 1. The dental care device has an interchangeable care part 12 which, in the exemplary embodiment shown, consists of a plate-shaped carrier 3 made of plastic and a bristle trim 4 composed of a plurality of bundles 5 which are connected to the carrier 3 in a known manner.

The head 1 has on its underside a depression in the form of a trough 6, the outline and contour of which correspond to that of the carrier 3.

The interchangeable care part 2 or its carrier 3 is snapped into the recess 6 of the head 1 and can be replaced by releasing the latching connection. In the exemplary embodiment shown, the latching connection is formed in that the support has individual projections 7 or strip-like ribs on at least two opposite sides (FIG. 3), which correspond with corresponding depressions 8 on the side cheeks 9 of the head. The inner contour of the recess 6 in the head 1 and the outer contour of the carrier 3 are matched to one another with close tolerances, so that a tight fit of the care part in the head 1 is ensured.

The head 1 has a continuous opening 11 on its back 10, into which a pin formed on the carrier 3 12 engages. The pin 12 is guided in the opening 11.

A pressure piece 13 in the form of an elastic disk 14, for example made of an elastomer, is arranged in the area of the opening 11 and closes the opening 11 on the back 10 of the head 1 and merges flush with the surface of the back 10. The disc 14 is slightly arched with respect to the surface contour of the back 10 and has a finger recess 15 in its center.

The disc 14 abuts the pin 12 on the carrier 3, so that when pressure is exerted on the disc 14, the compressive force is transferred to the pin 12 and the care part 4 can be ejected by releasing the latching connection 7, 8.

In the exemplary embodiment shown in FIGS. 1 to 3, the disk 14 is connected to the head 1 in a so-called in-mold process on the occasion of the injection molding, in a tight and non-positive manner, or is also glued in place.

In the embodiment according to FIG. 4, the recess 6 on the head 1 and the carrier 3 of the exchangeable care part 2 are designed differently. First, the head 1, as in the embodiment according to FIGS. 1 to 3, has an opening 11, the wall of which, however, is drawn into the trough 6 and has thickenings 16 at its free ends, which cooperate with spring catches 17 on the back of the carrier 3 . For this purpose, the spring catches 17 have depressions 18 adapted to the thickenings 16 on their inside. Conversely, the inwardly projecting wall can of course also be designed to be resilient in the form of individually standing wall sections. In this embodiment, the carrier 3 also has a pin 19 which, in deviation from FIGS. 1 to 3, is not guided in the opening 11. The pressure piece 13 is again designed in the form of a disk 14 which spans the opening 11, but in this case is fixed on the edge side to projections 20 on the inner wall of the opening 11. The disk 14 can be used mechanically or in turn can be connected to the head 1 in the in-mold process. Welding or gluing is also possible for fastening the disk 14.

The worn-out care part 2 is ejected in the same way by pressure on the disc 14, which is transferred to the pin 19 and leads to the detachment of the latching connection 16, 17 and 18.

Claims

claims

1. Dental care device with a handle, a head (1) and a care part (2) which can be latched in a recess (6) in the same, which is arranged by means of a resilient pressure piece (13) arranged on the back (10) of the head, which at Pressurization acts on the back of the care part, can be ejected, characterized in that the head (1) on the back (10) has an opening (11) which is closed by the pressure piece (13) and into which the care part (8) engages, and in that the pressure piece is designed as a flexible disc (14) made of plastic and is sealed with its peripheral edge on the wall of the opening (11).

2. Dental care device according to claim 1, characterized gekenn¬ characterized in that the care part (2) on its in the trough (6) of the head (1) lying back has a pin (12) which in the opening (11) to the Engages disc (14).

3. Dental care device according to claim 2, characterized gekenn¬ characterized in that the pin (12) is guided in the opening (11).

4. Dental care device according to one of claims 1 to 3, characterized in that the disc (14) on the edge with the surface of the back (10) on the head (1) is flush and is curved towards the center towards the outside.

5. Dental care device according to one of claims 1 to 4, characterized in that the disc (14) consists of a different plastic than the head (1).

6. Dental care device according to claim 5, characterized gekenn¬ characterized in that the disc (14) consists of an elastomer.

7. Dental care device according to claim 5 or 6, characterized in that the disc (14) relative to the head (1) is optically lifted.

8. Dental care device according to one of claims 1 to 7, characterized in that the disc (14) is positively, materially or non-positively inserted into the opening (11) of the head (1).

9. Dental care device according to one of claims 1 to 8, characterized in that the disc (14) is injected on the occasion of the injection molding of the head (1) in the in-mold process.

CORRECTED SHEET (RULE 91) ISA / EP