WO2009001391A1

WO2009001391A1 - Method for the manufacture of frames for spectacles and a spectacle frame thus obtained

Info

Publication number: WO2009001391A1
Application number: PCT/IT2008/000411
Authority: WO
Inventors: Gioachino Busatta
Original assignee: Valmec S.R.L.
Priority date: 2007-06-27
Filing date: 2008-06-19
Publication date: 2008-12-31
Also published as: ITPD20070220A1

Abstract

A method for the manufacture of a frame for spectacles comprises the step of: - preparing a core configured so as to reproduce the surface of at least a portion of the frame, - applying to the core a covering of composite material comprising one or more layers of fibres immersed in a matrix of polymeric material.

Description

METHOD FOR THE MANUFACTURE OF FRAMES FOR SPECTACLES AND A

SPECTACLE FRAME THUS OBTAINED DESCRIPTION The subject of the present invention is a method for the manufacture of frames for spectacles, of the type including the characteristics mentioned in the preamble of the main claim, and a spectacle frame obtained by means of the method.

In this field the need has recently arisen for producing frames comprising parts made of composite material comprising fibres, for example carbon fibres, capable of imparting to such parts an appearance of particular aesthetic value.

Within this scope it is known to produce parts of spectacle frames constituted by composite material based on carbon fibre and obtained by means of hot moulding. The process typically provides for the laying out of a number of layers of carbon fibres pre-impregnated with a thermosetting polymeric material, for example an epoxy resin, inside a heated mould, which is then closed. By suitable selection of the closure time and the temperature of the mould, the crosslinking of the thermosetting polymer is induced, with consequent hardening of the composite material. The semi-manufactured product thus obtained is then extracted from the mould and subsequently processed on a machine tool in order to obtain the final workpiece, corresponding to the required frame part. In particular, in the case where the part corresponds to the front frame of the spectacles, by means of moulding, a solid semi-manufactured workpiece is obtained in which, by means of milling, the holes corresponding to the lens- holding rims and the seats for receiving the lenses are provided. The main drawback of such a process lies in the fact that the material selected and the sequence of operations described involve significantly high manufacturing costs and times compared with those that are typical in the field of frames for spectacles.

In the case of the front frame, for the construction of the lens-holding rims it is necessary for the moulding operations to be followed by milling work which involves, at the same time, a high wastage of composite material. A further drawback is represented by the production drawbacks typical of the manufacture of objects made of composite material with stratified fibres. The difficulty of accurately controlling the positioning of the fibres in fact results in the possibility of irregular surfaces on the finished workpiece, and the larger the number of layers of fibres present, the greater this is. It is an aim of the present invention to provide a method for the manufacture of frames for spectacles, and a spectacle frame thus obtained, in such a way as to remedy the drawbacks mentioned with reference to the prior art cited. This aim, and others which will become clear hereinafter, are targeted and achieved by the invention by means of a method for the manufacture of frames for spectacles which is carried out according to the following claims. The characteristics and advantages of the invention will become clearer from the detailed description of a preferred exemplary embodiment thereof, provided by way of non-limiting example with reference to the appended drawings, in which:

Figure 1 is an axonometric view from above of the frame of Figure 1; - Figure 2 is a front view of a detail of the frame of Figure 1; - Figure 3 is a diagrammatic representation of a section along the line III- III of Figure 2;

Figures 4 and 5 are respective front and rear views, in opposed directions, of a semi-manufactured form of the constructional detail of Figure 2;

- Figure 6 is a front view of a component of a pair of spectacles that can be associated with the frame of Figure 1;

Figure 7 is a rear view of a pair of spectacles comprising the frame of Figure 1 and the component of Figure 6, assembled to each other. in the figures listed above, the reference 1 indicates as a whole a frame for spectacles which lends itself to being obtained by the method of the present invention.

The frame 1, having a configuration which is conventional per se, comprises a front frame 2, in which a pair of lens-holding rims 3 are provided, between which a bridge 4 extends. The front frame 2 comprises a pair of lateral lugs 5 which in an articulated manner, by means of a pair of hinges 6, connect the front frame 2 to a pair of arms 7, which are conventional per se. The method of the present invention initially provides for the step of preparing a core 8 of aluminium, or aluminium alloy, configured in such a way as to reproduce the surface of the front frame 2. The core 8 is prepared by means of a first milling of a flat plate, with which a template 9 is obtained, having a predominantly planar course, of a shape corresponding to the core 8. The template 9, on the side facing towards the lugs 5, comprises two grooves 10a, b respectively extending along the peripheral edge of each of the lens-holding rims 3. The grooves 10a, b are connected by means of a further groove 10c, provided at the bridge 4.

The core 8 is obtained from the template 9 by means of subsequent bending, performed on a number of planes by the use of a corresponding mask or bending mould. According to an alternative embodiment, the method of the present invention initially provides for the step of preparing a core (not shown) by means of pressing or moulding a metal alloy or a plastics material. On the core 8, at the lateral lugs 5, respective holes 11 are provided, each of which can be coupled to a respective hinge 6. Following this is the step of applying to the core 8 a covering 12 of composite material. The covering 12 includes at least one layer of fibres immersed in a matrix of thermosetting polymeric material. According to the alternative embodiment shown in Figures 1 to 7, the covering 12 comprises at least one layer of fabric made of carbon fibres. Preferably, the covering 12 comprises two superposed layers 13a, b, of carbon fibres. In general, however, any number of layers of fibres may be conveniently used, to be selected for each specific application according to the functional and aesthetic characteristics, and the cost, of the covering 12. According to other alternative embodiments, the method of the present invention provides for the manufacture of frames (not shown) comprising other types of fibre, for example aramide fibre or metallised aramide fibre. In general, as the thermosetting polymeric material, any polymer capable of forming, by means of crosslinking, a compact matrix for the layers of fibres, is used. For example, a polymer based on epoxy resin may conveniently be used. The covering 12 is applied to the core 8 by means of a hot moulding process.

The process provides, first of all, for disposing on the core 8 a first layer 13a and a second layer 13b, superposed on the layer 13a. The two layers 13a, b are of fabric made of carbon fibres and impregnated with non-crosslinked epoxy resin. The layers 13a, b are applied to the core 8 in such a way that the respective edges 20a, b come to lie in the grooves 10a, b,c (Figure 3). The core 8 covered with the layers 13 is then inserted into a heated mould (not shown) coated internally with rubber. The rubber allows the mould to adapt better to the shape of the core 8, in particular of the undercut parts. The mould is closed on the covered core 8 so as to effect the crosslinking of the epoxy resin and the consequent solidification of the covering 12. The mould is then opened and the workpiece, corresponding to the front frame 2, is extracted. Two holes are made in the covering 12, corresponding to the holes 11 in the lateral lugs of the core 8, so as to permit the coupling of the hinges 6 with the holes 11. The fixing of the arms 7 to the hinges 6 completes the manufacture of the frame 1.

On the front frame 2, the grooves 10a, b,c covered by the covering 12 define a seat for removably receiving a lens-holding insert 15, comprising a pair of lenses 16. The insert 15 comprises a support 17 made of acetate. As an alternative to acetate, another material such as PVC, or wood or cork or a metal alloy may be used. On the support 17, a central portion 17c is defined, that can be coupled to the groove 10c on the bridge, and two pairs of forks 17a, b, extending from the central zone 17c in opposite directions. Between the forks 17a, b, the lenses 16 are received in engagement. From the central portion 17c rises a pair of small lugs 18, conventional per se, incorporated in the support 17. The insert 15 is coupled to the front frame by interlocking. The assembly consisting of the frame 1 and insert 15 defines as a whole a pair of spectacles 19.

The present invention therefore solves the problem mentioned with reference to the prior art cited, making it possible to obtain a method for the manufacture of spectacle frames having a surface of fibre-based composite material, characterized by reduced manufacturing times and costs compared with the prior art cited. In particular, in the manufacture of the front frame 2, the use of the core 8 makes it possible to apply a smaller number of layers of fibres and to eliminate the need to provide the lens-holding rims by means of processing on a machine tool. The reduced number of layers of fibres at the same time permits better control of their arrangement, making it possible to obtain more even finished surfaces. The method of the present invention at the same time provides further advantages compared with the prior art cited.

These include the fact that the presence of the seat 14 for coupling with the lens-holding insert 15 makes it possible to arrange the edges of the fibres in a non-visible part of the frame. The frame thus obtained therefore lends itself particularly to preassembled mounting.

Claims

C L A I M S

1. A method for the manufacture of a frame for spectacles, comprising the step of: preparing a core configured so as to reproduce the surface of at least a portion of said frame,

- applying to said core a covering of composite material comprising at least one layer of fibres immersed in a matrix of polymeric material.

2. A method according to claim 1, wherein said layer is made of carbon fibre and said polymeric material is based on epoxy resin.

3. A method according to claim 1 or claim 2, wherein said covering is obtained by means of hot moulding.

4. A method according to any one of the preceding claims, wherein said step of preparing said core comprises at least one milling operation.

5. A method according to any one of the preceding claims, wherein said step of preparing said core comprises the operations of:

- providing, by milling a flat plate, a template having a predominantly planar course, of a shape corresponding to said core,

- bending said template in order to obtain said core of said front frame.

6. A method according to claim 5, wherein said flat plate is made of metallic material.

7. A method according to claim 6, wherein said metallic material is aluminium or aluminium alloy.

8. A method according to any one of the preceding claims, wherein said step of preparing said core comprises at least one moulding operation.

9. A method according to any one of the preceding claims, wherein said core is made of plastics material.

10. A method according to any one of the preceding claims, wherein said core is made of composite material.

11. A method according to any one of the preceding claims, wherein said core reproduces the entire front frame of said frame.

12. A method according to claim 11, wherein said at least one layer of fibre is applied to said core in such a way that the edges of the fibres lie in at least one seat for receiving lenses.

13. A method according to claim 12, wherein an insert comprising a pair of lenses is removably received in said seat.

14. A method according to claim 12 or claim 13, wherein at least one groove provided on said core corresponds to said seat.

15. A method according to claims 5 and 14, wherein said groove is provided on said template during the operation of milling said template.

16. A frame for spectacles, comprising, a core configured so as to reproduce the surface of at least a portion of said frame, - a covering for said core including at least one layer of fibres immersed in a matrix of polymeric material.

17. Spectacles comprising a frame according to claim 16.