TECHNICAL FIELD The present invention relates to a hinge with micrometric angular adjustment.

More particularly, the present invention relates to a hinge that may particularly, though not exclusively be used in co-operation with an orthopedic brace, said hinge allowing a micrometric adjustment of the opening or closing angle of the hinge in respect of a predetermined reference point.

The invention has a main application in the field of the precision mechanical industry.

BACKGROUND ART Some braces known in the art are used in case of monodepartmental degenerative diseases of knee articulation, such as for instance in case of genu varum or genu valgum, arthrosis of the medial and lateral behaviour, tibial osteoporosis.

A brace of this kind is generally constituted by a first rigid upper structure, that is buckled around the upper part of the leg, a second rigid lower structure, that is buckled to the lower part of the leg, as well as by a central thrust element, that is suitable for tensioning the knee articulation with a predetermined force acting from a lateral direction.

Such thrust element is connected to the upper and lower rigid structures by means of a pair of hinges,

whereby each hinge allows a fine adjustment of the connecting angle between a respective rigid structure and said thrust element to be carried out.

Documents US-A-5421810, US-A-5400806, US-A-5086760 disclose some forms of embodiment of braces provided of hinges with micrometric adjustment of the inclination angle between two connected parts.

The hinges disclosed in said documents involve some disadvantages and drawbacks.

By way of example, the hinge described in document US-A-5421810 comprises several mechanical parts requiring very high working accuracy and tolerances while their assembly, what causes relatively high costs.

Furthermore, once this hinge is assembled on the brace, it shows some parts which protrude laterally from the knee, what is very bothering to the patient, who always reports remarkable difficulties for wearing clothes upon the brace, which is also a source of potential accidents.

Simi-lar considerations can be expressed in what concerns the angular compensation device described in document WO-A-97/40789.

In this case the pivot of the hinge and the wings connected thereto co-operate with an arcuated bar by means of guide studs, while a double-threaded screw allows an angular compensation to be carried out.

In this case too, we have to point out a remarkable complexity of the hinge form a mechanical point of view, as well as the discomforts and the potential dangers which the patient is subjected to by the arcuated bar that protrudes laterally in respect of the knee.

DESCRIPTION OF THE INVENTION The present invention aims to set aside the inconveniences and drawbacks which are typical of the background art, and to provide for an improved hinge with micrometric adjustment which is consti-tuted by very few mechanical elements, which is easy to be assembled, which allows a remarkable angular adjustment accuracy to be achieved and, moreover, which does not form a source of discomfort or potential dangers for the patient who uses a brace provided of such hinge.

This is obtained by means of a hinge having the features disclosed in the main claim.

The dependent claims outline particularly advantageous forms of embodiment of the hinge according to the invention.

Furthermore, claim 7 describes a brace for orthopedic use that is provided of a hinge according to the present invention.

The hinge according to the present invention is provided with a first element, or upper wing, and with a second element, or lower wing, as well as with a first rotation pivot that rotatably connects sad first element to said second element, said pivot being fixed to one of said first and second elements.

Thus, in particular said first pivot enables the rotation of one of these elements about the axis defined by said pivot which, as said before, is fixed to the other element.

According to a feature of the invention, said first pivot is provided, in a central portion of its side surface, of a series of teeth which are radially

positioned on the side surface, each tooth being parallel to the longitudinal axis of the pivot.

Furthermore, a second pivot is fixed to one of the wings, the second pivot's axis laying on a plane that is parallel to the plane on which the. axis of the first pivot lays, and which is perpendicular to the axis of the first pivot.

Said second pivot is provided, on its side surface, of an endless screw thread having a pitch corresponding to the distance separating two adjacent teeth placed in the central area of said first pivot.

In operation, the thread of the second pivot co- operates with the teeth of the first pivot, in such a way that a rotation about a predetermined angle of the second pivot corresponds to a rotation about a similarly predetermined angle of the first pivot.

In this way, by acting on the second pivot it is possible to carry out a fine and micrometric adjustment of the inclination angle of one of the elements of the hinge in-respect of the other one.

ILLUSTRATION OF DRAWINGS Other features and advantages of the invention will become apparent by reading the following description of a form of embodiment of the invention, given as a non- limiting example, with the help of the drawings illustrated in the attached sheets, in which: -fig. 1 shows a side section of a hinge according to the present invention; -fig. 2 shows a partially sectioned side view of the hinge of fig. 1; -fig. 3 shows a side view of the hinge of fig. 1;

-fig. 4 shows a plan view of the hinge of fig. 1; and -fig. 5 shows a perspective schematic view of a knee brace provided with a pair of hinges according to the present invention.

DESCRIPTION OF A FORM OF EMBODIMENT In figures 1 to 4, a hinge 100 comprises a first element or wing 10 constituted by a metallic sheet that is suitably sheared and folded so as to form a front portion 11, a rear portion 12 and a pair of substantially cylindrical seats 13,14 suitable for housing a pivot 20 which will be later described in detail.

Furthermore, hinge 100 comprises a second element or wing 20, which is also constituted by a metallic sheet that is suitably sheared and folded so as to form a front portion 31, a rear portion 32 as well as three substantially cylindrical seats 33,34,35 which are suitable for housing said pivot 20.

Yet, first element 10 comprises a pair of holes or caulkings 15,16 enabling the passage of suitable fastening means (not illustrated in the figures) by means of which pivot 20 is fixed and made integral to said first element 10, in such a way that a rotation movement of pivot 20 about its longitudinal axis A results in a corresponding movement of the whole first element 10 about the same axis 10.

Finally, first element 10 comprises, on its front and rear portions 11,12, respective holes 17,18 (18') which enable the passage of other fastening means, e. g. rivets 19 (see fig. 5) through which first element 10 is fixed to the mechanical piece that is connected to the hinge; in fig. 5 said mechanical piece is constituted by

the upper part of an orthopedic brace, e. g. a knee brace.

On the other side, second element 30 also comprises, on its front and rear portions 31,32, respective holes 36,37 (37'), suitable for enabling the passage of other fastening means, e. g. rivets 39 (see fig. through which second element 30 is fixed to the mechanical piece that is connected to the hinge. in fig. 5 said mechanical piece is constituted by the lower part of an orthopedic brace, e. g. a knee brace.

According to an important feature of the invention, pivot 20 is provided, in correspondence of its central part, that is normally placed inside of substantially cylindrical part 34 of second element 30, with a series of teeth 21 which are radially posiitioned adjacent to each other, and which are made on the side surface of the central portion of pivot 20; the tip of each tooth 21, as well as the cavities between adjacent teeth, have a curvilinear shape, in particular they are shaped as an arc of circle.

A second pivot 40, whose length is comparable to the base diameter of the cylindrical portions defined by the respective first and second elements 10,30 in correspondence of the folding area of the metal sheets, is inserted in a rotatable way about its longitudinal axis B (see fig. 1) between the respective front and rear portions 31,32 of second element 30 of hinge 100.

In particular, according to the form of embodiment shown in the figures, portions 31,32 are provided of two holes, the centres of which are aligned to axis B, while second pivot 40 is provided, in correspondence of both ends thereof, with respective cavities inserted inside of

said holes; however, pivot 40 may still be rotated about axis B.

Pivot 40 has (see in particular figure 4) a head showing a rectilinear slot 41 inside of which a suitable tool, in particular a screwdriver, can be inserted, in order to carry out the rotation of pivot 40 about axis B.

According to another important feature of the invention, pivot 40 is provided with a side surface shaped as an endless screw; therefore, it shows a series of threads 42 which are suitable for being inserted in the cavities between teeth 21 of pivot 20; in this context it has to be noticed that endless screw 42 constituted by the side surface of pivot 40 has a pitch line having a diameter which is substantially equal to the virtual diameter of the circumference defined by the arcuated portions of the cavities placed between adjacent teeth 21 of pivot 20.

According to a further feature of the invention, the pitch of endless screw 42 of second pivot 40 and the distance-between respective teeth 21 of first pivot 20 are selected in such a way that a given rotation angle of pivot 40 about its axis B corresponds to another predetermined angle of pivot 20 about axis A; this features allows some very interesting applications of hinge 100 to be carried out.

According to a particularly advantageous form of embodiment of the invention, pivot 20 is provided with eight teeth 21 distributed upon its side surface.

This configuration corresponds to a pitch of 1,57 mm of endless screw 42.

In these conditions, a 180° rotation of pivot 40

about axis B corresponds to a 30° rotation of pivot 20 about axis A.

Now, in the case where hinge 100 is used to connect two respective parts 50,60, or 70,60 of a brace 80, as illustrated in fig. 5, it appears tombe clear that by acting on pivot 20 of either hinge it is possible to carry out a micrometric adjustment of the inclination angle of respective parts 50 and/or 70 in respect of central part 60 of a brace as the one shown in fig. 5.

Hinge 100 illustrated in fig. 4 is particularly suitable for being used for connecting to each other parts 50 and 60, or 70 and 60, of a brace as the one shown in fig. 5.

As it can be observed in fig. 4, second element 30 of the hinge is provided with a graduated scale 43 that is radially placed arounf the centre of pivot 40, while cavity 41 of the pivot, inside of which a screwdriver is inserted, is aligned to the central index of graduated scale 43 when both elements 10,30 lay on the same plane.

In these conditions, a 90° clockwise rotation of pivot 40 results in a 15° inclination in a given direction of first element 10 in respect of second element 30; similarly, a 90° counterclockwise rotation results in a 15° inclination of first element 10 in respect of second element 30, though in an opposed direction.

It is evident that a smaller rotation of pivot 40 about axis B corresponds to a smaller rotation of pivot 20 about axis A, therefore to smaller rotations of element 10 relative to element 30.

From the previous description it is possible to

understand that hinge 100 according to the present invention allows all the cited disadvantages and drawbacks, which are typical of the background art, to be overcome.

In fact, the hinge according to-the invention is constituted by only four pieces (two wings and two pivots), and it is extremely flat: its height is much smaller than the height of the known hinges which are used in cooperation with orthopedic devices.

Furthermore, it appears to be clear that although 10 according to the invention has a practical application in connection to orthopedic devices as the above-described one, the teachings of the present invention can be used in order to realise orthopedic braces for wrists, elbows, hips, ankles and shoulders.

In particular, the hinge according to the invention is specifically suitable for being used in connection with those braces which are provided of a thrust element suitable for relieving the pressures (and the pain deriving-therefrom) acting on sick articulations, e. g. in case of osteoarthritic pains.

The invention has previously been described with reference to an advantageous form of embodiment thereof.

However, it is clear that the invention is not limited to this specific form of embodiment, and it englobes all equivalent variants in what concerns its design, falling within the scopes of the invention as claimed.