GB2352830A

GB2352830A - One piece plastics spectacle frame

Info

Publication number: GB2352830A
Application number: GB9912828A
Authority: GB
Inventors: Adam Peter Derbyshire; Thomas Henry Marsden
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-06-02
Filing date: 1999-06-02
Publication date: 2001-02-07
Also published as: GB9912828D0; WO2000075715A1; AU5093300A

Abstract

A one-piece plastics material spectacle frame 10 comprises a front portion and at least one integral arm 20, with integral hinge means 50 which permits folding of at least one of the arms towards the front portion. The hinge 50 may comprise grooves 60. A one piece plastics spectacle frame comprises a front portion and two arms depending from it, at least one of the arms extending at less than 90{ to the plane of the front portion eg at 50{. Lens tabs (80, Fig 5) may be provided on the rear of the front portion to allow ventilation behind lenses as worn.

Description

2352830 SPECTACLE FRAMIE The present invention relates to spectacle frames

and a method of manufacturing spectacle frames.

Many designs of spectacle frames for both reading glasses and sunglasses exist in the prior art. However, these frame designs comprise one of two basic types. The first, and most common, type comprises three or more frame elements, typically a front lens-bearing portion and two arms which are hingedly connected. Often these hinges are spring-loaded, for example by a biased spring mechanism, thereby biasing the legs of the spectacle frame into an open or folded position relative to the rest of the frame.

The manufacture of such a frame is a multi-stage process requiring the manufacture of at least a front lens-bearing frame portion, two arms, and various hinge components. This is followed by the assembly of all these components together which involves the careful attachment of each arm to the front frame portion by means of a hinge often including a small screw. This is a complicated and time-consuming process, and therefore relatively costly.

Once assembled, the hinge portion can wear out through repeated use, thereby necessitating the repair of the frames. Also, the screws attaching the hinge to the frame loosen as the arms of the frame are repeatedly moved about the hinge and may eventually fall out. Further, often where there is a screw holding the frame tight around a lens, that screw may become loose, thereby allowing the lens to drop out of the frame resulting in possible breakage or loss of the lens.

A further disadvantage of such known frames is that often the hinges do not allow the arms of the frame to grip the head of the wearer sufficiently firmly to be retained in place during movement, especially during physical activity. They are likely to either slip on the head and require pushing back into their original position, or to fall off the head of the user, possibly resulting in damage to the frame or to any lenses held in the frame. In order to counteract 2 this problem sleeves are added to the side arms that provide more grip and stability. These sleeves add to the manufacturing list of required parts thus increasing overall cost.

The second type of frame comprise a rigid one-piece frame in which the arms of the frame are formed integrally with the front frame portion, rather than being formed separately and attached to the front frame portion by means of a hinge. An example of this type of frame can be found in US 5760868. This type of frame is bulky and therefore inconvenient to carry as the arms of the frame cannot be folded towards the front frame portion to usefully reduce the size of the frame for carrying or storing when not in use. This frame-type cannot be collapsed into a compact folded arrangement in the way that the hinged frame-types can be collapsed.

The object of the present invention is to address the problems of the prior art.

Accordingly, a first aspect of the invention provides a one-piece plastics material spectacle frame comprising a front frame portion and at least one integral arm, with integral hinge means which permits folding of at least one of the arms towards the front portion. This is advantageous because the frame can be economically manufactured and includes less components which might wear or be lost.

The hinge means might be in the form of a portion of the frame which consists of a different material to the remainder of the frame or is arranged in some other way to facilitate folding. For example, the hinge means may comprise a section of a material which is incorporated with the remainder of the frame. Alternatively, the frame may be increased or reduced in thickness at the hinge recess so as to facilitate folding of an arm towards the front portion. For example, the frame material may bemechanically or chemically treated to increase its flexibility at the hinge means. Where the frame is reduced in thickness, the hinge means may comprise at least one groove or other recess extending across an arm of the frame. Preferably, the groove extends across the width of the arm.

The one-piece spectacle frame may comprise at least one thermoplastic material, such as ethylene vinyl acetate (EVA) or polyurethane, or may comprise at least one thermoplastic elastomer. These types of material have the advantage that they have a 'memory'.

3 Therefore, if the arms of the frame are eased apart away from the front portion of the frame or folded together towards the front portion then once they are released, they spring back to their original position relative to the rest of the frame. A thermoplastic elastomer is defined as being less rigid than a thermoplastic material. However, a thermoplastic material may be of sufficient flexibility to be appropriate for use in the manufacture of one-piece spectacle frames.

According to another aspect of the invention, there is provided a one piece spectacle frame comprising a front portion and two arms depending therefrom in which at least one of the arms extends at less than 901 to the plane of the front portion.

Preferably, the ann extends at less than 75', more preferably the arm extends at between 40' and 60'. Even more preferably, the arm extends at 50'C to the plane of the front portion.

The one-piece spectacle frame may comprise a iolding clip which holds the arms of the frame in a folded position. The clip may be associated with one of the arms of the spectacle frame when not clipped to the other arm. For example, the clip may be hinged to the arm so that it can be hinged between a clipped position where it engages the other arm and out of use position where it does not interfere with the user's comfort. Alternatively, the arms may fold together in an interlocking arrangement so as to hold each other in a folded position when not in use.

According to a further aspect of the invention, there is provided a method of producing a spectacle frame comprising forming the front and arm portions as an integral unit and forming separately, and at the same time, hinge means which permit folding of at least one arm towards the front portion of the frame.

The one-piece spectacle frame may be manufactured by injection moulding. This process requires a hardened mould, manufactured to a specific design and specification, to be used in combination with an injection moulding machine.

The hinge means may be formed at the same time as the remainder of the frame by moulding reduced thickness portions of the arms.

4 The hinge means may be formed separately by mechanically or chemically or physically treating the frame. For example, reduced thickness portions might be machined onto the frame or the frame could be heat or cold treated to alter the physical properties of the frame material in the hinge means portion.

Spectacle frames and methods for production of spectacle frames in accordance with the present invention will now be described by way of example only, and with reference to Figs. I to 6, in which:

Figs. I(A) to I(C) are plan views of a first embodiment of the present invention in progressively more folded arrangements; Figs. I (D) to I (F) are enlarged views of a portion of the frame shown in Figs. I (A) to I (C) respectively; Figs. 2(A) to 2(D) are plan views of a frame according to a first embodiment in progressively more unfolded arrangements; Fig. 3(A) is an elevation of a frame according to a first embodiment of the invention; Figure 3(B) is an enlarged portion of a leg portion of the frame shown in Fig. 3(A); Fig. 4 is an elevation of the front frame portion of a frame according to a first embodiment of the present invention; and Fig. 5 is an elevation of a frame according to Figure 4; and Fig. 6(A) is a rear elevation of a frame according to a first embodiment of the present invention; and Fig. 7(B) is a rear elevation of a frame according to Fig. 6(A) in a folded arrangement.

As shown in Fig. 1, the frame 10 is formed in one piece. The frame 10 is manufactured by injection moulding using a thermoplastic material, such as EVA, or polyurethane. The arms 20 of the frame 10 are angled towards each other such that the frame has a substantially triangular shape when viewed from above, as shown in Fig. I (A).

Specifically, each arm extends at an angle of about 50' from the plane AA of the front portion when the frame is in an unfolded condition.

The frame 10 is provided with a hinge portion 50, which comprises a plurality of grooves 60 in the frame 10 at the junction between the front of the frame 10 and each arm 20. The plurality of grooves 60 are positioned in the rear surface of the frame 10. The position of the grooves facilitates folds of the arms and allows the arms 20 to be repeatedly folded about the same groove, and the thermoplastic material of which the frame is composed ensures that the arms 20 retain their ability to spring back into the triangular frame shape each time the arms 20 are deformed away from this position and then released.

In order for a user to wear the frames, the arms 20 of the frame can be eased apart in order to be positioned on the head of a user, as shown in Fig. 2(D). The frame shape and the memory of the material results in the arms 20 trying to return to their original position within the triangular frame shape. This results in the arms 20 firmly gripping the head of the user once in place on the user's head, thereby retaining the frames in position. Due to the elastic properties of the thermoplastic material, the arms 20 can be eased apart during use, and will then spring back to their triangular shape when removed from the head.

When not in use, the arms 20 of the frames can be folded inwardly, about the hinge grooves 60, towards the rear surface of the front 30 of the frames 10, as shown in Fig. 6(A). Once the arms 20 of the frames have been folded inwardly, the arms 20 are retained in the folded position by interlocking with each other such that the arms cannot spring apart again, as shown in Fig. 6(B).

As well as the memory of the thermoplastic material ensuring that the arms 20 return to their original position after deformation, the thermoplastic material also allows the front of the frames to be eased apart to allow insertion or removal of tenses from the frame. To insert a lens into the lens retention portion 70 of the frame 10, the lens retention portion 70 is stretched so that the lens can be inserted, and the lens retention portion 70 then released to allow the thermoplastic material to return to its original position, thereby gripping the lens firmly in position within the frame. The lens can be removed again in a similar manner.

6 A further embodiment is shown in Fig. 5 which is provided with lens tabs 80. These lens tabs allow ventilation of the lenses by allowing an airflow behind the lens, to prevent the lenses misting in moist environments. This is especially beneficial in cold conditions during physical activity where warm air trapped behind the lens would condense on contact with the cold lens for example, during skiing etc. The lens tab may be conveniently eased away from the front portion 30 of the frame 10 to allow removal and/or insertion of a lens within the lenses retaining portion 70 of the frame 10.

In a further embodiment, the lens may be incorporated during the manufacture of the frame. During the injection moulding process, the lens may be moulded using a suitably transparent material. This would be particularly useful in the inexpensive production of safety glasses and sunglasses, although it would also be possible to incorporate prescription lenses in the frame during the manufacturing process.

Claims

7 Claims

1. A one-piece plastics material spectacle frame comprising a front portion and at least one integral arm, with integral hinge means which permits folding of at least one of the arms towards the front portion.

2. A one-piece plastics material spectacle frame according to claim 1, wherein the hinge means comprises a different plastics material to the rest of the frame.

3. A one-piece plastics material spectacle frame according to claim I or claim 2, wherein the hinge means is weakened relative to the rest of the frame.

4. A one-piece plastics material spectacle frame according to claim 1 or claim 2, wherein the hinge means is reduced in thickness relative to the rest of the frame.

5. A one-piece plastics material spectacle frame according to claim 4, wherein the hinge means comprises a groove or recess.

6. A one-piece plastics material spectacle frame according to claim 5, wherein the groove or recess extends across at least a portion of the arm.

7. A one-piece plastics material spectacle frame according to any preceding claim, wherein the hinge means is mechanically or chemically treated to increase its flexibility.

8. A one-piece plastics material spectacle frame according to any preceding claim comprised of at least one thermoplastic material.

9. A one-piece plastics material spectacle frame according to claim 8, wherein the thermoplastic material is EVA or polyurethane.

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10. A one piece plastics material spectacle frame according to claim 8, wherein the thermoplastic material is a thermoplastic elastomer.

11. A one-piece plastics material spectacle frame comprising a front portion and two arms depending therefrom in which at least one of the arms extends at less than 90' to the plane of the front portion.

12. A one-piece plastics material spectacle frame according to claim 11, wherein the arm extends at an angle of less than 750 to the plane of the front portion.

13. A one-piece plastics material spectacle frame according to claim 12, wherein the arm extends at an angle of between 400 and 60' to the plane of the front portion.

14. A one-piece plastics material spectacle frame according to claim 13 wherein the arm extends at an angle of 500 to the plane of the front portion.

15. A one-piece plastics material spectacle frame according to any preceding claim comprising a clip means which holds the arms of the frame in a folded arrangement.

16. A one-piece plastics material spectacle frame according to claim 15, wherein the clip is associated with one of the arms of the frame when not clipped to the other arm of the frame.

17. A one-piece plastics material spectacle frame according to claim 16, wherein the clip is hinged to one of the arms.

18. A method of producing a spectacle frame comprising forming front and arm portions as an integral unit and forming separately, at the same time, hinge means which permit folding of at least one arm towards the front portion of the frame.

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19. A method according to claim 18, wherein the hinge means is formed by moulding a reduced thickness portion of the arms.

20. A method according to claim 18, wherein the hinge means is formed by mechanically or chemically or physically treating the frame.

21. A method according to claim 20, wherein the mechanical treatment comprises machining reduced thickness portions in the arms.

22. A method according to claim 20, wherein the physical treatment comprises heat or cold treatment.