HINGE FOR AUTOMATIC CLOSURE OF SPECTACLE ARMS

This invention is a new type of articulated joint that is fitted between the arms and the front tip of the spectacles, by means of which hinge the arm closes automatically when it has been removed from the head or from any other agent that causes the arms to stay open in relation to the front of the spectacles.

The original feature of this invention is the fact that it consists of a reel or drum onto which an elastic device is wound that is attached to one end of the hinge and adapted to house and hold in position the end of a spring. The other end of the spring is held in position in a box that contains it and centres it. This box is fitted to the other end of the hinge that is to be assembled and is internally provided with viscous antifriction material that gradually makes the elastic device expand as a reaction to closure.

Many different hinge systems are known, particularly those between the arms and the edges of the frames of spectacles. These usually use a closure screw between a flat revolving part that is housed and immobilised between two fixed parts of which one is usually threaded in order to ensure that the centring screw is held firmly in position.

All these hinge systems are fitted to items of very small dimensions and this is a first disadvantage because of the difficulty of axially aligning the parts that need to be joined.

Attempts have been made to overcome this disadvantage through alternative solutions that eliminated the use of centring screws. But these solutions were too complicated and were often not reliable and for this reason the established technique remains that of fitting a closure and centring screw, despite the aforementioned disadvantages that this brings.

Moreover, normal hinges for spectacles need to accompany the arms for the whole of the closure stroke.

To overcome this last disadvantage, a very large number of systems have been devised to make the hinge connecting the arms to the front of the spectacles elastic.

All these systems are designed to ensure that the arms open sufficiently, especially when the wearer puts on the spectacles, and are also designed to make the arms snap into the closed position when they are not in use.

All the known systems of elastic opening are not only complicated and therefore costly but they also enable only a limited opening of the arms in relation to the frame to which they are hinged. During the closure phase, these systems of elastic opening also require the arms to be given an initial push in order to enable the arms to overcome an initial point of inertia.

In all present spectacle frames, both of the normal and elastic type, a stop prevents the arms from opening beyond a certain point; the repeated knocking against these stops damages the frame and alters the position of the lenses in relation to the bridge and the nose rest that link them.

The aim of this invention is to enable spectacles to be produced that are able to gradually come to lie completely flat on the frame by themselves without being pushed, as soon as there is nothing keeping them open.

Another aim of the invention is to produce glasses that are fitted with arms to the opening of which virtually no limit is set. This will eliminate all risks of deformation of the frame whilst it will guarantee adequate pressure of the arms on the temples.

A further aim of the invention was to devise a spectacle frame that was free of the traditional and inconvenient system of a centring screw or pivot.

Yet another aim of the invention was to devise a hinge enabling elastic opening that would be both extremely simple and therefore also sufficiently hardwearing and long lasting.

These and other aims have been completely achieved by this invention, as can be seen from the following description of one of the forms that it might take. This description is purely illustrative and not restrictive and also uses the 5 schematic figures shown in the attached plates:

• fig. 1 of plate 1 is a view in perspective, from behind a spectacle frame, of a part of the device in question as applied to the nose rest or edge of the frame;
• fig. 2 of plate 1 is a view in perspective of the tip of an arm that has been fitted with another part of this invention;
• fig. 3 of plate 1 shows a vertical, detailed view of an axial section of the main parts of the device;
• fig. 4 of plate 2 shows a vertical view of an axial section of the same parts as those in figure 3 that have been fitted together;
• fig. 5 of plate 2 is a plan view of the frame of a pair of spectacles fitted with hinges that connect the arms to the frame and which hinges have been manufactured in accordance with the invention.

In all the figures, the same elements have been shown or shall be deemed to have been shown, with the same reference number.

The figures on the attached plates show a spectacle frame (F) that is fitted with a nose rest or edge (M) of the traditional type.

A drum (1) is fixed to or at least firmly held in position on the nose rest (M). The drum (1) is fitted with a groove(2) that also has a guideway (3) on the hub (4) that has a through hole or dead hole (5).

The drum (1) is first placed in space (11) of a cylindrical box (10), the bottom of which (12) is fixed to or firmly connected to the arm (A). Next, the drum (1) is fixed to a nose rest (M).

The box (10) has two or more through holes (13) on the cylindrical surface (14). One or more holes (13) should be threaded to accommodate a screw (15).

The groove(2) of the drum or reel (1) houses a spiral spring (20), the inside end of which (21) is housed in the guideway (3) and the hole (5) of the drum (1). The outside end (22) is passed into one of the holes (13) of the box (10).

These are the simple and small number of main parts of the hinge. The assembly system and its main functions will now be summarised, partly in order to ascertain how fully it achieves the preset aims.

First, a suitable quantity of viscous material (30) is deposited into the space (11) of box (10). This may be of a polybutane or silicon based type or it may be made of an antifriction type material such as Teflon.

The drum is next positioned in the space (11) of the box (10). The quantity of material (30) that has already been applied to the space (11) must be such as to enable the axes of the holes (13) to be aligned with the axis of the groove(2) of the drum (1) that is fitted there.

In order to fit the elastic device (20) in the best position, align a hole (13) of the box (10) with the hole (5) of the drum (1) and insert one end (21) of the wire of the spiral spring (20). This may be in straight or preformed sections of a preset length.

If the box (10) has already been fixed to the arm (A) and if the drum (1) still has to be fixed to the nose rest (M), the drum (1) is immobilised with a jig. Arm (A) and then the box (10) are made to complete a number of revolutions so that the elastic device (20) is completely wrapped around a single spiral spring on the hub (4) of the groove(2). Only the edge (22) of the elastic device (20) is allowed to protrude from the hole (13) of the box (10). For obvious reasons of convenience, the head (22) of the spring (20) should be fitted with a head that has a diameter that is greater than the holes (13).

A series of screws (15) or threaded grub screws of the required length are inserted into the holes (13) or the box (10) in order to prevent the spiral spring (20) from leaving its pre-loaded position.

The screws or threaded grub screws (15) occupy the groove (2) in order to prevent the drum (1) from escaping from the box (20).

When the hinge has been thus prepared, it is fixed to the nose rest (M) by means of welding or another system of fixing so that the nose rest (M) is fixed to the top surface of the drum (1) in such a way that the arm (A) is definitively fitted to the frame (F).

Pre-loading the spring (20) ensures that the arm will rotate towards the frame (F), to its natural closed position

Under normal opening pressure, the arm (A) and the box (10) to which it is fixed can be made to rotate with practically unlimited opening range in relation to the frame (F) because there is no stop that limits maximum opening, as is shown in figure 5. This overcomes the problem of deformation of the frame, which is one of the stated aims.

After the action or pressure of opening is stopped, the pre-loaded elastic device, which is further stretched by the opening of arm (A), tends to make arm (A) rotate rapidly towards its closure position on frame (F).

The retarding action of the viscous material (30) counteracts the reaction of the elastic device (20). If the drum (1) is placed in the seat (11), the previously applied viscous material (30) sticks not only to the base (12) of the box (10) but also to the base (6) of the drum (1).

In this way, when the arm (A) has been opened, it gradually and independently returns to the closed position, which is one of its designed aims.

Of course, the density of the viscous material or other anti-friction material (30) and the degree of pre-loading of the spiral spring (20) must be properly established according to the speed at which the arms are required to close.

The manufacturing solution illustrated, as already specified, shall be deemed to be merely indicative and not restrictive, just like the assembly system exemplified. This is because it is also, for example, possible to connect the drum (1) to the arm (A) and connect the box (10) to the nose rest (M). It is also possible to directly connect box (10) to the drum (1) directly to the eye piece of the frame without placing a nose rest (M) between them. Equally the arms (A) or nose rests (M) can be fixed to the hinge using any system.

These modifications and other modifications shall nevertheless be deemed to form part of the original features of the invention to be protected by patent.