More particularly, the present invention refers to a device allowing a coil spring mechanism building up a resilient hinge to be released from the arm which it is fastened to, in the case where a component thereof is broken or becomes unusable.

BACKGROUNDART There are spectacle arms known in the art which are integral or rigidly fixed to boxes containing hinge mechanisms for rotating said arms.

Said boxes containing resilient hinge mechanisms can be fixed to their respective arms through glueing o welding, in particular when the latter are made of a metallic material; on the other hand they can be made integral to said arms, this solution being commonly used when their manufacturing material is a synthetic one, particularly a plastic one, owing to evident reasons deriving form their intrinsic characteristics bound to the better workability of plastics.

Actually, injection moulding techniques can easily be used, through which a single operation results in manufacturing the arms and inserting therein the boxes while the plastic material has a temperature enabling its mouldability.

The resilient hinge mechanisms allow the arms to be resiliently widened beyond their resting position in

their configuration of use, i. e. the position where they stay at right angles relative to the spectacle frontal frame.

The presence of such mechanisms results in a better adjustability of the spectacle frame to the specific characteristics of the face of the person wearing this frame; more particularly, an enhanced wearing comfort derives from the use of these mechanisms, since there is a reduced pressure of the arms on the temples when the spectacles are worn.

A resilient hinge mechanism well known in the art is constituted by a hinge element comprising a cylindrical rod inserted within a containment sleeve and within a coil spring.

The sleeve is supporte by the hinge element on one side, and bears the coil spring on the other side.

At its other end, the coil spring is supporte by an ajustable stopping element, such as for instance a nut having a rounded or other suitable shape, or a washer cooperating with the end portion of the cylindrical rod.

The whole device, except the hinge element portion that receives the transversal hole connecting the hinge to the frontal frame, is housed inside of the rod containing box, and it is fixed to the latter by means of a screw which is inserted within a transversal hole drilled in the same containment box.

Said screw exerts a pressure on the flexible sleeve wall.

This configuration involves the disadvantage that while manufacturing, the resilient hinge mechanism assemblying operation and its fastening to the box should necessarily be carried out in distinct moments of time, a firstly inserting the mechanism inside of the

box, and thereafter screwing up the fastening screw.

Other solutions have been investigated in order to overcome this inconvenience; among these, the screw has been replace by a pivot integral to the resilient hinge mechanism, said pivot being engaged within a corresponding hole realised in the box. This solution allows the mechanism to be snapped to the box.

However, the obtained fixing is not reversible.

Moreover, the mechanism may be fixed by punching or squeezing the box, thereby causing some deformations that fasten the various components to each other in a fixed and irremovable way.

However, in the latter cases too, the manufacturing operation requires two distinct operations, i. e. the insertion of the mechanism inside of the box, and the punching or squeezing of the same, in order to fasten it.

Furthermore, although these solutions make the operations to be accomplished easier, they do not allow the mechanism to be extracted from the box.

As a consequence, in case of failures, breakings or yieldings of the mechanism the whole arm needs anyway to be replace while manufacturing the spectacles, since the insertion operation of the resilient hinge mechanism is carried out by a suitable machine, or while using the spectacles, what causes high costs either to the manufacturer, or to the user.

DESCRIPTION OF THE INVENTION The present invention aims to set aside the inconveniences and drawbacks which are typical of the prior art, and to provide for a simple and cheap solution allowing the resilient hinge mechanism to be inserted inside of the receiving box and fastened to the latter in a single operation and in a reversible and

removable way, thereby allowing said mechanism, or a component thereof, to be replace in case of failures, breakings or yieldings, without needing the replacement of the whole arm.

This is achieved by means of a device having the features disclosed in the main claim.

The dependent claims outline particularly advantageous forms of embodiment of the present invention.

According to the present invention, a pair of holes are realised at the opposed ends of the box receiving the resilient hinge mechanism; the whole mechanism and, when needed, the hinge element, can be extracted from one of these holes, while a suitable tool can be inserted into the other hole in order to loosen and thereafter to remove the screw and the spring associated thereto.

According to another feature of the invention, the resilient hinge mechanism comprises a screw inserted within a coil spring and within a sleeve adjacent thereto, said screw being engaged in a longitudinal threaded hole realised in a hinge element.

Said coil spring is supporte by one end by the screw head, while the other end is borne by the sleeve which, on its turn, is supporte on its opposed end by the hinge element.

The containment sleeve is provided with two flexible wings which protrude above the hinge element when the resilient hinge mechanism is inserted into the box, and which are opened when reaching a suitable cavity realised in the box, thereby irremovably engaging a series of grooves realised in the walls of said cavity.

ILLUSTRATION OF DRAWINGS Other features and avantages of the invention will become apparent by reading the following description, given as a non-limiting example, with the help of the figure shown in the attache drawing, which shows, in a partially sectioned exploded view, a spectacle arm having a containment box and a resilient hinge mechanism.

DESCRIPTION OF A FORM OF EMBODIMENT Referring to fig. 1, reference sign 10 indicates a resilient hinge mechanism according to the invention; mechanism 10 is, in operation, housed inside of a box 30 that is either integral or welded or glued or spot- welded or injection-placed or anyway fixed to a spectacle arm 50.

Said box 30, that can be made of any synthetic or metallic material, is provided with two end holes, respectively 31 and 31', one of which is realised in the front side 61, while the other one is realised in the rear side 61'.

Having a closer down look on the figure, mechan. ism 10 is constituted by a hinge element 11 having a transversal through-hole 12, and which is suitable for cooperating with a complementary hinge element that is fixed to the spectacle front frame by means of a suitable pivot (not shown in the figure), as well as a longitudinal threaded dead hole 13.

The inner portion 16 of a sleeve 15 is supporte on side 14 of the hinge element. Said sleeve 15 is constituted by a preferably metallic element provided with a pair of reinforcing ribs (see for instance rib 17) directe towards said hinge element, said ribs being flexible and elongated, and they define two opposed arcs extending for a circle's quarter. At the opposed side

there are two wings 18,18'which are provided, at their ends, of a relatively strong reinforcing rib 20, said wings being rotated by about 90° relative to ribs 17.

In operation, flexible ribs 17 cover two of the four larger sides of the hinge element; one of these sides is indicated by reference sign 19 in the figure.

On the other hand, ends 20 of wings 18,18'of sleeve 15 act as supporting shoulder for a coil spring that is longitudinally crossed by a screw 22, whose head 23 acts as second supporting shoulder.

Said screw 22, after crossing said sleeve 15, is screwed into threaded hole 13 of the hinge element.

When resilient hinge mechanism 10 is inserted within box 30 through front hole 31 of box 30, flexible wings 18 and 18', which are tensioned while being pressed against the inner walls 33 of hinge element 11, suddenly reach a cavity inside of which they release their tension, are opened and are engaged within said cavity. Any movement of sleeve 15 from this position is, in this way, prevented.

It may be noted that a screwing action of screw 22 inside of hole 13 causes a compression of spring 21, whose upper base (in the figure) forces wings 18,18'in order to further broaden them, thereby enhancing the effect of fastening mechanism 10 inside of box 30.

Simultaneously, ribs 17 are engaged to the inner wall of the box, thereby further stabilizing the irremovable position of the mechanism inside of the cavity of box 30.

In case of breakings, mechanical yieldings or any other failure requiring the replacement either of said resilient hinge mechanism 10, or of one or more elements thereof, irrespective whether this happens while manufacturing or using the spectacles, it will not be

necessary to replace the whole arm as according to the known solutions.

Actually, it will suffice to extract the hinge element of mechanism 10 from front hole 31 and, by means of a suitable tool, to extract screw 22 and coil spring 21 from sleeve 15 through rear hole 31'.

According to a further form of of embodiment of the present invention, cavity 33 may be provided, on all its surface, with circular and parallel engravings which are suitable for blocking resilient hinge mechanism 10 through the engagement of the wing 18,18'edges within said engravings.

Therefore, the mechanism can be fixed in a more effective way by choosing among different adjacent fixing points, thereby allowing a more precise placement of the mechanism to be achieved, based upon a predetermined tensioning to be obtained while using the spectacle, as well as upon particular facial characteristics of the person wearing said spectacle.

Furthermore, it can be noted that, thanks to the presence of rear hole 31', it is possible to act on screw 23 head by means of a suitable tool and to modify the compression force of the spring, that means adjusting the resilient return force of mechanism 10; this is never possible with the solutions known in the art.

According to a further form of embodiment, said circular grooves have a knurled shape, in order to enhance their holding force on flexible wings 18,18'of sleeve 15 and to allow a more stable positioning of mechanism 10 inside of receiving box 30 to be achieved.

The invention has previously been described with reference to a particular form of embodiment thereof.

However, it is clear that the invention is not

limited to this form of embodiment, and that it encompasses all the variants that are conceivable within the scope of mechanical equivalences, or those which do not require the exercise of any inventive skill.

For instance, the invention comprises forms of embodiment according to which the threaded body of the screw is fixed to the hinge element, and the sping is held by a nut that is suitably screwed on the free end of the screw body.

According to other forms of embodiment, the screw head may have different shapes, as socket, star or other.