The present invention relates to a toothbrush having a top side and a bottom side opposite the former, having a head on whose top side are provided tooth-cleaning elements, having a handle which has a recess and having a neck connecting the head to the handle, such that a longitudinal direction of the toothbrush extends from one free end of the handle to the free end of the head.

US 5,908,038 discloses a toothbrush of the type defined in the preamble, having a recess in the handle area for reducing the cost of materials. However, as a smaller amount of plastic material is used for the toothbrush body, it becomes more difficult to provide a toothbrush that can be handled well with no change .

Therefore, the object of the present invention is to provide a toothbrush, which can be manufactured at a low cost using less plastic material and which on the other hand can be used conveniently and ergonomically by humans for the various types of toothbrush handling which vary greatly in different cultures around the globe.

This object is achieved by a toothbrush having the features of Claim 1. The toothbrush thus has a recess designed so that a handle depression at least one finger's width in size is formed by wall sections bordering the recess toward the outside. The handle depression is thus not formed by the wall sections bordering the recess toward the outside but instead is formed by the outer bordering wall sections of the recess formed in conjunction with the remaining cross-sectional shape of the outer handle area. The handle depression formed in this way is at least designed to be a finger's width in size, so that improved handling of the toothbrush is possible due to the handle depression, despite the reduced use of material due to the recess . Other advantageous refinements of the inventions are defined in the dependent claims.

In an advantageous further embodiment, the handle depression has two elevated flanks or supporting shoulders for the finger arranged opposite one another in the longitudinal direction of the toothbrush. In one variant, at least one elevated flank and/or supporting shoulder is provided. This prevents slippage of one's finger in the longitudinal direction of the toothbrush toward the head or toward the opposite free end of the handle for the finger held in the handle depression.

In an advantageous further embodiment, the distance between the flank high points amounts to at least one centimeter. This ensures that the handle depression is designed to be approximately one finger's width and a person's finger can be held well in the handle depression.

In an advantageous further embodiment of the invention, at least two, three or four handle depressions are formed on the handle by the recesses. The recesses may be differentiated from one another by partitions or may develop fluidly one into the other without partitions and thereby form a large joint recess. By providing four handle depressions, for example, it is possible for the thumb to be placed reliably on one side of the toothbrush handle while the other four fingers also find handle depressions around the recess to allow toothbrush to be gripped reliably by the entire hand. As already explained above, the handle depression is not formed by the inner depth extent of the recess but instead by the wall sections of the recess which border it toward the outside, in particular in cooperation with the remaining shape of the handle.

In another advantageous embodiment, the at least one recess is arranged on the side of the handle opposite the side with the tooth-cleaning elements and is open only toward the bottom side of the handle, so that the handle walls and/or wall sections bordering the at least one recess form an inverted U when seen in cross section, i.e., 90° across the longitudinal direction of the toothbrush. Due to the recess on the bottom side of the toothbrush, which is surrounded by walls on three sides as seen in cross section, good unmoldability of the toothbrush from the injection mold is ensured with no change. Furthermore, the U- shaped structure forms a mechanically rigid structure in the cross section of the wall sections around the recess, so the overall strength of the toothbrush is adequate. For example, in the case of recesses which form a passage through the toothbrush head on both sides, the flexural rigidity is much worse if material is to be saved in the handle area to the same extent as in the present case.

In an advantageous further embodiment, the side walls of the handle form a taper. The taper in combination with the handle depressions thus forms another improvement in the ergonomic design of the toothbrush and in the variability of the possibilities for use of the toothbrush for Asian users in particular. In addition, the taper ensures further savings of material even in the outside area of the handle because a widening of the cross section is provided only in the end areas of the handle, i.e., at the locations where the enlarged outside cross section of the handle contributes toward an ergonomic improvement .

In another advantageous embodiment of the invention, the handle has one thumb rest each on the top side and on the bottom side adjacent to the neck. In the present case, the thumb rest on the bottom side is formed by the depression in the recess in the handle. The thumb rest has an elevated supporting structure in its edge areas, in particular in the longitudinal direction of the toothbrush, so that the user's thumb rests securely on both sides of the toothbrush between these elevated flanks or supporting structures or shoulders and does not slip off or slip into the recess during use.

In another advantageous embodiment, the top side of the handle has multiple finger-width recesses. The surface structure of the top side is thus not smooth but instead is structured with slight indentations (a few millimeters) so that all of a user's fingers also find a secure hold on the top side of the handle, depending on the user's tooth-cleaning technique. The indentations here are designed to be slight because the recess in the handle is formed on the back side of the indentations.

In another advantageous embodiment, the outline of the bottom side of the handle describes a concave curvature. Thus, in a side view of the toothbrush, the bottom side of the handle is curved in an arc shape, such that the end sections of the bottom side of the handle describe the lowest points in the arc of curvature and the area of the bottom side of the handle approximately at the center in the side view of the toothbrush describes the high point of the arc curvature. Here again, plastic material is thus saved in the handle area because the basic shape of the bottom side of the handle is designed so that the only handle walls provided there are those considered necessary for ergonomic reasons .

In another advantageous embodiment of the invention, the U-shaped handle walls point toward the top side of the handle so the handle wall connecting the two U-legs has a thinner wall thickness than the side walls and/or side legs of the U-shaped cross section. An increased flexural rigidity is thus achieved in the lateral direction relative to the longitudinal direction of the toothbrush, while the toothbrush allows increased flexibility in handling in the direction of the extent of the tooth-cleaning elements and/or bristles. In addition, this results in a different decorative effective for the top side relative to the side walls.

In another advantageous embodiment, the at least one recess is formed by a hollow cavity in an elliptical shape. In a plane parallel to the receiving surface for the tooth-cleaning elements on the head, the depressions have an elliptical shape. In another advantageous embodiment, the at least one elliptical cavity is aligned in the handle, so that the narrow side is adjacent to the side walls and the longitudinal sides of the elliptical forms are aligned with the free ends of the toothbrush.

In another advantageous embodiment of the invention, several elliptical cavities are formed by the recesses and are open toward one another in the longitudinal direction, i.e., are delineated without partitions, so that the individual elliptical cavities and/or recesses form a large shared depression. The design of the depression as an elliptical cavity facilitates an advantageous means of providing handle depressions around the recesses .

In another advantageous embodiment of the invention, the toothbrush is made of polypropylene. The toothbrush can thus be produced especially easily by the injection molding method.

In addition, the toothbrush can be manufactured by mono-component injection molding. As an alternative, the toothbrush may be manufactured by multi-component injection molding and optionally also provided with soft components such as thermoplastic elastomers .

These and other features are derived not only from the claims but also from the following description, the preferred exemplary embodiments and the respective drawings, where the features, either alone or in any combination, may constitute the subject matter of the invention independently of how they are combined with one another in the claims. In the drawings:

Fig. 1 shows a perspective diagram of the top side of a toothbrush according to the invention,

Fig. 2 shows a top view of the top side of the toothbrush according to Fig. 1, Fig. 3 shows a side diagram of the toothbrush according to Fig. 1,

Fig. 4 shows a longitudinal sectional diagram through the toothbrush according to Fig. 1 along the line of intersection A-A in Fig. 2,

Fig. 5 shows a top view of the bottom side of the toothbrush according to Fig. 1, and

Fig. 6 shows a perspective diagram of the bottom side of the toothbrush according to Fig. 1.

Fig. 1 shows a perspective diagram of the top side of a toothbrush having a head 1, a neck 2 connected thereto and a handle 3 which is in turn connected to the neck. The top side of the toothbrush has tooth-cleaning elements in the form of bristle clusters 4 in the area of the head 1. The top side of the handle 3 has a thumb rest 5 designed as an indentation in the surface structure. The thumb rest 5 has a supporting shoulder 6 in particular in the longitudinal direction of the toothbrush toward the head and a supporting shoulder 7 in the longitudinal direction of the toothbrush toward the free end 8 of the handle. The thumb rest is designed with an elliptical shape, as shown in particular by the top view of the toothbrush in Fig. 2, and is provided with concentric elliptical fluting, which additionally increase the grip in the area of the thumb rest. The top side of the handle 3 has additional indentations 9, 10, 11 and 12, which extend only a few millimeters into the structure of the surface of the handle and are connected to the thumb rest toward the free end 13 and are designed like the thumb rest to be as wide as a finger's width in the longitudinal direction. The indentations 9, 10, 11 and 12 are also essentially elliptical in design, so that inclined supporting shoulders for the fingers are formed around the recesses. In deviation from the elliptical design of the indentations presented here, they may also have a different geometric shape. The top view of the toothbrush according to Fig. 2 also shows a definite taper 14 of the handle 3. The taper 14 is thus provided in a plane approximately parallel to the bristle embedding plane 17 of the head 1. In this plane an enlarged outline cross section 15 is provided around the thumb rest 5 and at the other end of the handle next to the free end 13 there is an enlarged cross section of the handle 16.

As shown in Fig. 3, which shows a side view of the toothbrush, the taper is also slightly pronounced in the side view of the toothbrush approximately in the central area. The toothbrush has an approximately s-shaped basic shape from its free end 13 on the handle end up to the free end 20 on the head end. The top side 18 of the toothbrush has several supporting shoulders and/or high points which delineate the individual ellipses and/or the finger indentations 5, 9, 10, 11, 12 therein from one another. The bottom side 19 of the toothbrush has a concave and/or bow-shaped curvature in the handle area toward the center of the handle. Thus, in a side view of the toothbrush, a deeper section 21 is formed opposite the thumb rest 5 on the end of the handle next to the neck 2 and at the other end of the handle next to the free end 13, another deeper section 22 is formed. This greater curvature of the bottom side of the handle toward the inside is reproduced less markedly by the top side of the handle toward the outside as seen in a side view. The bottom side of the handle not only has a concave curvature toward the interior of the toothbrush but instead its outline is also designed to have a slightly wavy structure, as seen in a side view. This wavy shape 23 is also determined by the various handle depressions on the bottom side 19 of the handle 3 because the handle depressions on the bottom side are delineated from one another by flanks and/or shoulders and ultimately by high points. A first handle depression is also formed on the bottom side 19 next to the neck on the same end but opposite the thumb rest 5 on the top side. The thumb or index finger may thus be held in the handle depression 24 on the bottom side 19 next to the neck. The handle depression 24 has two elevated flanks 29, 30 arranged opposite one another in the longitudinal direction of the toothbrush, in particular along the longitudinal axis A-A in Fig 2. The one flank 29 of the handle depression 24 is thus arranged next to the neck and prevents the finger accommodated in the handle depression from slipping off toward the neck, and the other shoulder or flank 30 of the handle depression 24 is arranged facing the free end 13. Similarly, additional handle depressions 25, 26, 27 and 28 are formed on the bottom side 19 of the handle 3. On the whole, this handle thus provides five finger indentations on the top side of the handle and five corresponding handle depressions on the bottom side of the handle. Alternatively, fewer indentations or handle depressions may be formed. An especially good grip of the toothbrush and good handling are ensured due to the plurality of handle depressions and the resulting wavy-shaped outline structure along the bottom side of the handle.

Fig. 4 shows a longitudinal sectional diagram through the toothbrush along line A-A in Fig. 2. In the non-hatched area on the bottom side 19 of the handle 3, there are recesses 31, 32, 33, 34 and 35, which in this embodiment are not separated from one another by partitions and thus form a large common recess. These recesses 31 to 35 are bordered in the transverse direction by three walls, namely side walls 36 and 37 (see Fig. 5) and the inner rear side 38 of the top side of the handle area 3. These three walls form an uninverted U in the cross-sectional plane that runs perpendicular to and across the sectional line A-A in Fig. 2. The recesses thus extend over the entire handle area of the toothbrush. Only one transitional area of the handle toward the free end 13 and a transitional area of the handle toward the neck are not provided with this recess. The inlet area of the recess 31 is bordered by a wall section 39 of this recess 31, which forms a border toward the outside. These wall sections 39 of the recess 31 which form a border toward the outside form the supporting surface for a handle depression 24 the width of a finger. The recess along with this thumb rest area is designed to be essentially elliptical. The recesses and the other handle depressions on the bottom side of the handle are designed similarly . As shown in Fig. 5 and Fig. 6, the depressions 24 to 28 on the bottom side of the handle not only form a wavy shape with flank high points and concave indentations in the respective depressions in the handle around the recess, but also form a wavy shape as seen in a view from above onto the recesses 31 to 35 due to the respective elliptical shape of the cavity of the recesses. An elliptical recess in the area of the thumb rest is aligned with the next recess up to the end of the handle, so that the wall sections bordering the recess toward the outside, i.e., the transitional area between the inside of the recess and the outside, forms the finger rest areas and thus the depressions in the handle. There is thus a delineation of the depressions in the handle in two dimensions, namely in both the longitudinal direction and the transverse direction of the toothbrush, which is illustrated by the wavy shapes along the depressions in the bottom side of the handle according to the side view in Fig. 3 and the wavy shape in the view from above onto the bottom side of the toothbrush according to Fig. 5. The resulting deflection out of the bottom side of the handle due to the shape of the recesses is transferred from the bottom side of the handle, so that the bordering wall sections toward the outside form depressions of finger width in the handle. Finger width in this case means approximately at least 1 cm wide in the longitudinal direction of the depression the handle of the toothbrush. The length of the depression in the handle from one flank high point to the next flank high point of the adjacent depression in the handle in the longitudinal direction of the handle varies between 10 millimeters and 40 millimeters for the different depressions in the handle. Each depression in the bottom side of the handle is designed to be of a different size because this requires different amounts of space for the different fingers and the taper of the toothbrush handle influences the width and length of the depressions in the handle anyway.

The wall thickness of the top side of the handle which corresponds to the side of the tooth-cleaning elements is designed to be thinner in this variant than the wall thickness of the side walls 36 and 37 of the handle, resulting in a certain flexibility of the handle and the brush body in the plane through the section A-A in Fig. 2 and permitting a reduced flexibility of the toothbrush in the lateral direction.

Furthermore, the thinner design of the top side of the handle allows the implementation of other decorative structures, which appear with a lighter density than the other walls of the toothbrush when using a transparent or translucent plastic as the primary material for the toothbrush body.

As shown in Fig. 5 and Fig. 6, the toothbrush also has a tongue cleaner 40 formed by ribs on the bottom side of the head. However, the handle structure shown here can be combined with any bristle pattern or tongue-cleaning pattern or even without a tongue-cleaning pattern on the back side of the head. Furthermore, as an alternative, fewer depressions may be formed in the bottom side of the handle. In another variant, openings are also provided on the top side of the handle if the associated destabilization of the handle structure is desired. The toothbrush is made of polypropylene but could also be made of another plastic material. This toothbrush is produced from a plastic component by the injection molding process. Alternatively, other plastic components, in particular elastomer plastics may be formed on the head, the neck or handle area according to the multi-component injection molding process.