Abstract:
The present invention relates to a supporting device for an interdental cleaning means, of the type comprising a handle and a tightening head for an elongated appendix portion of said cleaning means, said tightening head comprising a central body around which a complementary rotating bush is mounted, and wherein said bush and said central body have a common hole for hosting said appendix portion, which hole is substantially parallel and offset relative to the rotation axis of the bush.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a supporting device for an interdental cleaning brush and the like. 
   DESCRIPTION OF THE RELATED ART 
   It is known that interdental cleaning brushes, which usually consist of a suitably shaped handle onto the free end of which a small disposable brushing body is mounted, are very diffused on the market. 
   Since it is suitable, for clear hygienic and practical reasons, that said small brushing body be frequently discarded and replaced with a new one, it is important that said body may be very easily and quickly engaged/disengaged with and from the shaped handle. 
   Known devices of this type are illustrated, for example, in U.S. Pat. No. 4,319,377, U.S. Pat. No. 4,222,143, EP 311,937 and EP 537,663. 
   All of these devices are designed so that a wire brush provided with an appendix portion, usually made from a twisted double metal wire, is attached to the handle. Such devices exploit the high deformability of said appendix, which is inserted into a through hole and then bent by about 90° against the handle, where it is blocked by a tightening element. 
   This approach has various drawbacks, among which there are:
         the required 90° bending of the metal appendix portion of the brush results in great deformation of the material, which may reach and exceed the yielding point and this may prevent further uses of the brush—e.g. re-attaching the brush after having first wrongly attached it; at any rate, the appendix must be made of materials elastic enough to bear such deformation, which, so far, has restricted the choice exclusively to metal materials;   the appendix portion, inserted into a through hole of the device, before being deformed and blocked, projects from the handle in a way that is dangerous for the user;   the device is necessarily provided with a room for hosting the inserted bent appendix portion: this implies the existence of a recess, where dirt and bacteria may easily accumulate;   finally, in order to bend the appendix portion and cover it completely, so that it does not remain exposed within the user&#39;s mouth, it is necessary that the (linear or angular) stroke of the moveable tightening element of the device be ample, which is not always easy to obtain, considered the very small size of said element.       

   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a supporting device for an interdental brush that eliminates the above-illustrated drawbacks, in particular through a tightening means that provides a secure block for the brush that also has a short angular stroke, that is able to hold appendix portions of various materials, that does not have any large, dirt-collecting recesses and that under no conditions allows the dangerous exposure of the pointed end of the appendix portion. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further advantages and features of the device according to the invention will however result from the following detailed description of some preferred embodiments, given by way of example and illustrated in the appended drawings, wherein: 
       FIG. 1  is an interrupted plan top view of a first embodiment of the device according to the invention; 
       FIG. 2  is an interrupted side elevation view of the device in  FIG. 1 , wherein the two-positions of the handle, relative to the tightening head, are indicated by a thin line; 
       FIG. 3  is a partially sectional view taken along the line III-III of  FIG. 2 ; 
       FIG. 4A  is a partially sectional view taken along line IV-IV of  FIG. 1 , in a loose condition of the brush; 
       FIG. 4B  is a view as the one in  FIG. 4A  in a blocked condition of the brush; 
       FIG. 5  is a front elevation view of the tightening head; and 
       FIGS. 6 ,  7 A,  7 B and  8  are views corresponding to, respectively, the views of  FIGS. 3 ,  4 A,  4 B and  5  concerning a second embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A supporting device for a brush is made, in a known manner, by a handle  1  onto the end of which a tightening head  2  is mounted, into which an interdental brush or similar instrument is removably attached. 
   According to the invention, the tightening head  2  comprises a central supporting body  21 , attached to the handle  1 , and a tightening bush  22  rotatably mounted onto the central body  21 . 
   The central body  21  is composed of a stem  21   a , through which it may engage the handle  1 , and an axially symmetrical core  21   b . Preferably, the core  21   b  is spherical and lightly depressed at the poles, as is well illustrated in the drawings. 
   The stem  21   a  is attached to the handle  1  through a hinged joint  21   c , which allows to rotate and orientate the head  2  in the direction indicated by the arrow R. Advantageously, the hinge may be obtained by overmoulding the end of the handle  1  onto the hinge  21   c , these two elements being of “incompatible” materials, therefore not weldable to each other during the overmoulding step. 
   The term “incompatible” must be understood as it is well described in EP 1075806, which is also in the name of the Applicant and shall also be considered included here as a reference. 
   In order to better guide the joint, the hinge  21   c  is shaped as a disc, the opposite bases of which being shaped like conical surfaces that are symmetrical relative to a rotation axis b-b′. In order to ensure a secure block, the hinge  21   c  is further provided with a central hole, coaxial with the rotation axis b-b′, into which material of the handle  1  is apt to penetrate during the overmoulding process, which is going to become a pivoting pin. 
   On the opposite bases of the hinging disc  21   c , low radial ribs are provided, which are designed to be inserted into corresponding grooves in the surrounding seat of the handle. The engagement of the ribs into the grooves ensures a stable angular positioning of the tightening head with respect to the handle, which may be modified by applying enough force to produce an elastic deformation of the ribs when moving from one groove to the next. 
   From the periphery of the core  21   b , at its equator, a short guiding stud  23  projects, the role of which will be illustrated hereinafter. 
   The tightening bush  22  is hollow and has an internal surface perfectly complementary to the revolving surface of the body  21 , thus having the same symmetry axis. The external surface may be differently shaped, for example with non-slip knurlings or studs  22   a , apt to make the bush comfortably usable by a person&#39;s fingers. 
   The bush  22  is further provided with a groove  24  along a circumferential arc of about 180°, at its equator, wherein the stud  23  is designed to move. 
   With this exemplary embodiment, the free rotation between the tightening bush  22  and the body  21  is guided and limited by the stud  23  being engaged into the groove  24 , according to what the arrow F illustrates in  FIG. 5 . 
   The rotation axis, in the embodiments illustrated in the drawings, coincides with the symmetry axis a-a′ of the tightening head  2 . 
   According to the invention, the body  21  and the bush  22  also have a common longitudinal blind hole  25 , placed eccentrically relative to the rotation axis a-a′, apt to host the appendix portion of a brush S. The eccentricity of the hole  25  may be determined depending on the diameter and on the material of which the brush appendix is made. 
   The hole  25  has a diameter that can quite loosely host the appendix part of the brush or other similar oral hygiene instrument. For example, the hole may have a diameter of 0,6 mm. 
   In an inoperative condition of the bush  22  and the body  21 , the respective portions of the hole  25  are aligned with each other ( FIGS. 3 and 4A ), therefore it is possible to freely insert therein (arrow D) and withdraw therefrom the appendix portion of the brush S. In this inoperative or idle state, the bush  22  is completely rotated in one direction and the stud  23  abuts against an end-of-travel wall of the groove  24  ( FIG. 1 ). 
   In an operative position of the bush  22  and the body  21 -obtainable by rotating the bush  22  from the inoperative position, e.g. in the direction indicated by the arrow F—the respective portions of the hole  25  are out of axis relative to each other on a common plane ( FIG. 4B ). As can be argued, this results in a tightening of the appendix portion of the brush S, which gets deformed and remains therefore securely fixed into the tightening head  2 . 
   The reaching of the operative tightened position is preferably indicated by an opposite end-of-travel wall of the groove  24 , against which the stud  23  abuts, for example, after a 180° rotation. 
   In order to assure the user that he or she has definitely reached the end-of-travel, as well as to avoid any involuntary rotations of the bush  22 , any known click-blocking system may be provided in the complete and secure tightened position of the brush. 
   For example, the groove  24  has a restriction near the end-of-travel, so that the user must put some effort to make the stud  23  pass behind the restriction. This way, the stud will stop at the end-of-travel and no accidental disengagement will be possible. Furthermore, the user will clearly perceive, due to the effort and to the snapping “click”, when the instrument reaches a secure operative position. 
   According to another embodiment, illustrated in  FIGS. 6-8 , the bush  22  and the body  21  have an axial hole  250  with a larger diameter, for example 3 mm, to host a so-called “rubber point”  260 , i.e. a small pin of a rubber material, to which abrasive material may be further added, having the function of an interdental instrument (such as a toothpick) or of a tooth-surface polishing instrument. 
   The tightening principle of the rubber point  260  is the same as the one illustrated above. 
   Obviously, such a hole  250 , having a large diameter, is not apt to block the appendix portion of a brush, which is typically thinner. 
   According to a further embodiment of the invention (not illustrated), the device of  FIGS. 6-8  is provided with a false rubber point, having the function of a tightening adapter, which may be added and sold to the public in the same package with which the whole device is sold. This adapter, made of easily deformable material (e.g. elastomeric material), is slightly longer than the blind hole  250  and has a tightening axial hole. 
   When use of a classical rubber point is desired, said adapter is extracted from the hole  250 . On the contrary, when one wishes to use an interdental brush on the same device, it is possible to insert the appendix part of the brush onto the tightening hole of the adapter and then tighten the latter inside the hole  250 , thus obtaining the simultaneous tightening of the adapter and of the brush. 
   It is however understood that the invention is not limited to the specific embodiments illustrated above, which only constitute non-limiting examples of the scope of the invention, but also many alternatives are possible, all within the reach of an expert in the field, without thereby departing from the scope of said invention.