Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
STIFF CASE, PARTICULARLY FOR GLASSES, OR SIMILAR
Document Type and Number:
WIPO Patent Application WO/2000/016656
Kind Code:
A1
Abstract:
A case, particularly for glasses, or similar, consists of two hinged (3) stiff half-shells (1, 2). According to the invention, the two half-shells (1, 2) are shaped in such a way as to be able to progressively fit one into the other, when the case is in the closed condition, while having different reciprocal snap closing positions (9, 10) corresponding to different positions of progressive insertion of the one (2) into the other (1).

Inventors:
CAFIERO ALDO (IT)
Application Number:
PCT/EP1998/005991
Publication Date:
March 30, 2000
Filing Date:
September 21, 1998
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
STUDIO PROMOZIONALI S N C (IT)
CAFIERO ALDO (IT)
International Classes:
A45C7/00; A45C11/04; A45C11/24; A45C13/10; (IPC1-7): A45C11/04; B65D21/08
Foreign References:
GB2255767A1992-11-18
FR1306254A1962-10-13
FR2652562A11991-04-05
US5261582A1993-11-16
EP0615707A11994-09-21
US3651983A1972-03-28
Attorney, Agent or Firm:
Karaghiosoff, Giorgio A. (27/B Celle Ligure, IT)
Download PDF:
Claims:
CLAIMS
1. A case, particularly for glasses, or similar, consisting of two hinged (3) stiff halfshells (1, 2), characterized in that the two halfshells (1,2) are shaped in such a way as to be able to progressively fit one into the other, when the case is in the closed condition, while having different reciprocal snap closing positions (9,10) corresponding to different positions of progressive insertion of the one (2) into the other (1).
2. A case as claimed in claim 1, characterized in that the means for snap closing through the different positions of progressive insertion of one halfshell (2) into the other (1) consist of a line of projections (10) on the inner side of the curved wall of the larger halfshell (1) and of an outwardly projecting cog (9) on the free edge of the smaller halfshell (2).
3. A case as claimed in claim 2, characterized in that the projections (10) are equally spaced.
4. A case as claimed in one or more of the preceding claims, characterized in that the projections (10) and/or the cog (9) have a rounded cross section, substantially like a cylindrical or elliptical sector, or like a lune sector, with lowslope faces.
5. A case as claimed in one or more of the preceding claims, characterized in that, in a substantially central position, on the inner side of the plane wall (5) of one of the two halfshells, i. e. of the bearing halfshell (2), there is provided a recess (7) on the outer side of the radial plane wall (5) of the halfshell (2), which acts as a member for grasping the corresponding halfshell by a hand, and which recess is dimensioned in such a way as to allow a finger of the hand to be at least partially housed therein.
6. A case as claimed in claim 5, characterized in that it has a protrusion (8), which is meant to engage under the nosepiece of the glasses frame instead of the nose, whereas the glasses are disposed with their lower side turned towards the curved wall and with their upper side in the area of the straight hinging side (3) of the two halfshells (1,2).
7. A case as claimed in claim 6, characterized in that the protrusion (8) is formed by the inner surface of the coincident grasping recess (7).
8. A case as claimed in one or more of the preceding claims, characterized in that it has means (11) for disengaging at least partially the retaining cog (9) from the line of projections (10).
9. A case as claimed in claim 8, characterized in that the partial disengaging means (11) consist of means for inward compression of the front wall (102) of the smaller halfshell (2), which bears the cog (9) or the line of projections (10), towards partial disengagement thereof from the associated line of projections (10) or from the cog (9) respectively on the inner side of the front wall (101) of the larger halfshell (1).
10. A case as claimed in one or more of the preceding claims, characterized in that the aligned projections (10) and/or the cog (9) have relatively steep faces (110,109) at their base and rounded profiles (210 and 209) at their apices.
11. A case as claimed in one or more of the preceding claims, characterized in that the apices (209,210) of the aligned projections (10) and of the cog (9) are chamfered, arched or rounded with surfaces whose radius is constant or progressively decreasing towards the apex thereof.
12. A case as claimed in claim 11, characterized in that the push means (11) for inwardly deforming the front wall (102) of the smaller halfshell (2), as well as the deformability characteristics of said wall (102) are such as to cause the line of projections (10) to move apart from the cog (9), at least to a partial extent and such that the aligned projections (10) and the cog (9) can interact substantially only with their respective rounded zones (209,210), thus obtaining a more harmonic and easier slipping motion of the two halfshells from the closed to the opening positions.
13. A case as claimed in one or more of the preceding claims, characterized in that the cog (9) and/or the aligned projections (10) may be, alternatively or in combination, asymmetrical with respect to the slope of their faces, and have steep faces on one side and less steep faces on the opposite side both on opposite faces and on faces oriented in the same directions.
14. A case as claimed in one or more of the preceding claims, characterized in that the cog (9), the line of projections (10) and the means (11) for inward compression of the front wall (102) are provided in the coincident median strips of the peripheral front walls (101,102) of the two halfshells (1,2).
15. A case as claimed in one or more of the preceding claims, characterized in that there are provided means for calibrating the elasticity and the deformability at least of the area of the wall (102) of the smaller halfshell (2) which bears the cog (9) or alternatively the line of cogs (10) and the push means (11) for at least partially disengaging them from the means (10,9) of the opposite halfshell (1), cooperating therewith.
16. A case as claimed in claim 15, characterized in that said means may consist, alternatively or in combination, in choosing the material which forms the whole wall (102), in providing a thinner wall at least in the part of the front wall (102) of the halfshell (2) whereon the cog (9), or alternatively the line of projections (10) and the push means (11) are provided, in connecting this part of the wall to the rest of the wall (102) by means of a hinging area or line made of a weakening or thinning line in the wall thickness at said hinging area or line, in making said wall area, or only the hinging area or line of a different material, having different deformability and elasticity characteristics, especially during the same molding process for the whole case, by means of coinjection methods.
17. A case as claimed in one or more of the preceding claims, characterized in that in order to be able to retain the larger halfshell (1), without deforming it under pressure so as to partially reduce the moving apart action caused by the inward pressure of the front wall (102) of the smaller half shell (2) there are provided means for calibrating the deformability of the larger halfshell (1) at least in the region of the line of projections (10), or alternatively of the cog (9) in such a way that it is less deformable than the corresponding region of the smaller halfshell (2).
18. A case as claimed in claim 17, characterized in that the front wall (101) of the larger halfshell (1) has, alternatively or in combination and at least in the area of the cog (9) or, alternatively, of the line of projections (10), stiffening arrangements, such as a wall stiffener, internal or external stiffening ribs, which may be crossed, integral or inserted and may also form a decoration pattern, the coinjection manufacture of this area in a different material, for example less flexible than the rest of the wall.
19. A case as claimed in one or more of the preceding claims, characterized in that the means for compressing the front wall (102) of the smaller half shell (2) are provided in such a position that they extend outside the larger halfshell (1), when said smaller one is in the completely inserted position, and consist of a grasping extension or a pushbutton, protruding out of the front side (102) of the smaller halfshell (2) beyond the front side (101) of the larger halfshell (1), when the case is in the closed condition.
20. A case as claimed in one or more of the preceding claims, characterized in that said grasping extension (11) extends parallel to the free edge (201) of the larger halfshell (1) and to that (202) of the smaller one (2) and is made in the form of a rib, wing or similar, having a certain length.
21. A case as claimed in one or more of the preceding claims, characterized in that the grasping tab (11) is advantageously also an endofstroke abutment in the mutual insertion of the two halfshells (1,2).
22. A case as claimed in one or more of the preceding claims, characterized in that it has projections, wings, ribs, blocks or endofstroke abutment extensions (12), which are provided inside the larger halfshell (1), and interact with the free front edge (202) of the smaller halfshell (2).
23. A case as claimed in one or more of the preceding claims, characterized in that said internal abutments (12) may be damped by providing that an abutment surface thereof is elastically compliant or by disposing on said surface a layer of elastic material, particularly foam, preferably made of the same padding lining material.
24. A case as claimed in one or more of the preceding claims, characterized in that the endof stroke abutments (12) are at least two. in number and are disposed substantially symmetrically to the vertical median plane at the two opposite end areas of the front wall (101) of the larger halfshell (1), and inside it.
25. A case as claimed in one or more of the preceding claims, characterized in that the larger halfshell (1) bears one, two or more lines of projections (10), and the smaller halfshell (2) bears one, two or more corresponding cogs (9) respectively, and at least one grasping extension (11) or push button, or vice versa.
26. A case as claimed in one or more of the preceding claims, characterized in that instead of one single cog (9), interacting with a line of projections (10), there may be provided a line of cogs (9) similar to the line of projections (10), composed of at least two adjacent cogs (9) and interacting with the line of projections (10).
27. A case as claimed in one or more of the preceding claims, characterized in that the two half shells (1,2) have the shape of a sector or a segment of a sphere, spheroid or ellipsoid, the radii of curvature or the greater and smaller diameters of one of the two halfshells (1,2) being slightly greater than those of the other one, and the two halfshells (1, 2) being hinged (3) about an axis which corresponds to a common chord connecting the opposite ends of the arched walls of the two halfshells (1,2).
28. A case as claimed in one or more of the preceding claims, characterized in that the curvature in the radial direction, with respect to the axis (3) about which the front walls of the two halfshells (1, 2) are hinged substantially corresponds to a circular curvature.
29. A case as claimed in one or more of the preceding claims, characterized in that, on the hinging side, each halfshell (1,2) is truncated, with a substantially plane rear wall (4), and the hinging axis (3) between the two halfshells (1, 2) is provided along the edge of said rear plane wall (4), on the open side of the halfshells (1,2).
30. A case as claimed in one or more of the preceding claims, characterized in that the halfshells have each, on opposite sides, a closed wall (5,6), which is substantially radial with respect to the hinging axis (3) or to an axis parallel thereto, which form the bearing side and the upper side of the case respectively.
31. A case as claimed in one or more of the preceding claims, characterized in that, alternatively to the line of projections (10), there is provided a line of cavities (10'), formed in their respective halfshell wall.
32. A case as claimed in one or more of the preceding claims, characterized in that the cog (9) and/or the line of projections (10) and/or the line of depressions or cavities (10') are lensshaped, having the form of a button, a dome and, respectively, of a complementary depression, where cavities (10') are concerned, and may have a circular, elliptical, ovoidal or similar plan shape.
33. A case as claimed in claims 31 and 32, characterized in that the curvature of the cog (9) and of the projections or cavities (10,10'), particularly as considered in the slipping direction of the cog through the line of projections or cavities, may be either constant or variable according to the desired higher or lower mutual engagement force, or to the softer or harder mutual slipping motion of the two halfshells through the different closing positions.
34. A case as claimed in one or more of the preceding claims 31 to 33, characterized in that the curvature transverse to the slipping direction may also affect to a certain extent the joint resistance and the slipping softness and may be constant or variable.
Description:
Stiff case, particularly for glasses, or similar The invention relates to a case for glasses or similar, consisting of two hinged rigid half-shells.

The object of the invention is to provide a stiff case of the type described hereinbefore, which is inexpensive and easy to manufacture and has an original look, is small-sized and able to easily fit different shapes and sizes of glasses, within the current size variations for frames.

The invention achieves the above objects by providing a case of the type described hereinbefore, in which the two half-shells are shaped in. such a way as to be able to progressively fit one into the other, while having different reciprocal snap positions corresponding to different positions of progressive insertion of one half-shell into the other.

According to a first embodiment, the two half- shells have the shape of a sector or a segment of a sphere, spheroid or ellipsoid, the radii of curvature or the greater and smaller diameters of one of the two half-shells being slightly greater than those of the other one, and the two half-shells being hinged about an axis which corresponds to a common chord connecting the opposite ends of the arched walls of the two half- shells.

The means for snap closing through the different positions of progressive insertion of one half-shell into the other consist of a line of equally spaced

projections on the inner side of the curved wall of the larger half-shell and of an outwardly projecting engaging cog on the free edge of the smaller half- shell.

Thanks to these arrangements, the case has a very attractive, and especially compact and resistant shape, and may quickly, simply and cheaply fit the size variations of glasses, while ensuring at the same time a good protection thereof.

In order to allow the case to be grasped and/or held when it is opened, the smaller half-shell, i. e. the one designed to fit inside the opposite larger half-shell is provided with grasping, holding means, consisting of a recess in the bottom side area, which recess is dimensioned in such a way as to hold at least a part of a finger to clench by the hand the two opposite surfaces, i. e. the rear hinging edge on one side, and the recess surface closer to said edge on the other side.

The line of projections is oriented along the opening arch, whereas the projections are arranged transverse thereto.

In this embodiment, the projections are provided with a cross section substantially having the shape of a sector of a circle, with round and relatively low- slope faces.

The cog may also be considerably rounded and have low-slope faces, since the seizure of the case upon opening thereof does not allow to act towards disengagement of said two parts.

The round profiles may be provided on one face only of the cog, particularly on the front face, with respect to the case closing direction, whereas the opposite face may be steeper.

Alternatively thereto or in combination therewith and for identical or different fronts, this may be also provided for the aligned projections.

According to an alternative embodiment, at the front side of the smaller half-shell, and outside the larger half-shell, when said smaller one is in the completely inserted position, on said front side there is provided a grasping extension, protruding beyond the front side of the larger half-shell, when the case is in the closed condition.

Advantageously, the grasping extension extends parallel to the free edges of the larger half-shell and/or of the smaller one.

This grasping extension acts, at the same time, as a push-button to be pressed inwards and backwards from the front side of the smaller half-shell, i. e. towards disengagement or partial disengagement of the cog from the line of projections.

Therefore, advantages are obtained from providing said grasping extension in the strip substantially coinciding with the cog and with the line of projections on the opposite half-shell.

Particularly, advantages are obtained from providing the cog, the line of projections and the grasping extension in the coincident median strips of the front peripheral walls of the two half-shells.

The grasping tab is advantageously also an end-of- stroke abutment in the insertion of one half-shell into the other.

Said end-of-stroke abutment is advantageously assisted by projections, wings, ribs, blocks or end-of- stroke abutment extensions, which are provided inside the larger half-shell, and interact with the free front edge of the smaller half-shell.

Preferably, these end-of-stroke abutments are at least two in number and are disposed substantially symmetrically to the vertical median plane at the two opposite end areas of the front wall of the larger half-shell, and inside it.

This embodiment allows to exert pressure for disengaging or at least partially disengaging the cog from the line of projections, and by making use of the elastic deformability of the walls, in this case of that of the smaller half-shell, and thanks to the grasping extension, the cog may be moved apart from the line of projections, thereby allowing softer closing and opening movements, while the cog is slipped on the line of projections.

In this case, both the cog and the aligned projections have much steeper faces at least at their base.

Advantageously, said cogs are chamfered, arched and rounded at the apices of the cog and of the projections, with surfaces whose radius is constant or progressively decreasing towards the apex of the cog and of the projections.

The depth of the cogs is also greater and their steeper faces allow to provide shorter distances between cogs and therefore a greater number of cogs all through the linear length of the line, hence a greater number of intermediate positions.

Thanks to the particular construction of these cogs, a stronger engagement force is provided in the closing positions, particularly in the positions other than the insertion end-of-stroke.

The grasping extension allows to partially move the line of projections apart from the cog, at least to a partial extent, such that the aligned projections and the cog can cooperate by their respective rounded parts.

As disclosed above, the movement of the cog apart from the line of projections towards partial disengagement therefrom may occur when the user presses the grasping extension which acts as a push-button, thanks to the intrinsic elasticity of the material.

Obviously, the elasticity and the compliance of the wall region associated to the cog and to the grasping extension or to the push-button may be calibrated by any method, and without weighing heavily on production costs.

The above arrangements may comprise the provision of a lower wall thickness on the part of the front wall of the half-shell where the cog and the grasping extension or the push-button are provided.

Alternatively, said wall region may be connected to the rest of the wall by a hinging zone or line, made

through a wall weakening or thinning line provided at said hinging zone or line.

A further variant may consist in that, by providing co-injection molds, the wall region associated to the cog or to the grasping extension, or the hinging zone or line are made of different materials, with different deformability and elasticity characteristics, during the same molding process for the whole case.

In order to be able to retain the larger half- shell, without deforming it under pressure so as to partially reduce the moving apart action caused by the inward pressure of the grasping extension or of the push-button associated to the smaller half-shell, it is also possible to calibrate the elasticity of the larger half-shell in the region of the line of projections in such a way that it is less deformable than the corresponding region of the smaller half-shell.

Also in this case, this may be provided by means of any stiffening arrangements, such as a thicker wall at least in the region of the line of projections, or through the whole front wall of the larger half-shell, the provision of internal or external stiffeners like ribs, or else, the co-injection production of said region from a different material, for example less flexible.

Although the above description relates to the larger half-shell bearing the line of projections and the smaller half-shell bearing the cog with the grasping extension or the push-button, the above

arrangements and advantages are obtained in the same way if the line of projections is alternatively provided in combination with the grasping extension or the push-button on the smaller half-shell and the cog is provided on the larger half-shell.

The improvements of the invention form the subject of the dependent claims.

The characteristics of the invention will be more apparent from the following description of a non- limiting example, illustrated in the annexed photographs, in which : Fig. 1 is a perspective view of a first embodiment of the invention, in the open condition.

Figs. 2 to 4 are different cross sectional views of the case as shown in fig. 1, in the open condition, closed at the first snap and completely closed.

Figs. 5A and 5B are enlarged cross sectional views of the region of the line of projections and of the engaging cog in the case as shown in fig. 1.

Fig. 6 is a perspective view of a second embodiment of the case according to the invention.

Figs. 7 to 9 are cross sectional views like those shown in figs. 2 to 4 of the case of fig. 6.

Figs. 10A and 10B show an enlarged detail like that shown in figs. 5A and 5B of the case of fig. 6.

Fig. 11 is a view like that shown in fig. 10, with the cog engaged in the line of projections, when no pressure is exerted on the grasping extension.

Fig. 12 is a side view like that shown in fig. 11, with the cog moved partially apart from the line of

projections, with pressure being exerted on the grasping extension, whereas, in dotted lines, the cog is shown in the complete engagement position.

Figures 13 and 14 are cross sectional perspective views of two further embodiments according to the invention.

With reference to figures 1 to. 5, the case according to the invention has two half-shells 1 and 2, preferably made of plastic.

The two half-shells 1,2 have the shape of a sector or a segment of a sphere, spheroid or ellipsoid, the radii of curvature or the greater and smaller diameters of one of the two half-shells 1 being slightly greater than those of the other one 2. The two half-shells are hinged about an axis 3 which corresponds to a common chord connecting the opposite ends of the arched walls of the two half-shells 1,2.

Particularly, the curvature in the radial direction, with respect to the hinging axis 3 substantially corresponds to a circular curvature.

On the hinging side, each half-shell is truncated, with a substantially plane wall 4, the hinging axis 3 between the two half-shells being provided along the edge of said rear plane wall 4, on the open side of the half-shell.

The rear plane wall 4 of the two half-shells may be also slightly inclined, in such a way that the two walls form an apex of an obtuse angle,. at the hinging axis 3. This advantageously prevents the rear walls 4 from exerting a pressure action possibly such as to

cause deformations on the glasses contained inside, when closing the case.

The radial closed walls 5,6 of each half-shell are plane and form the bearing side and the upper side respectively.

In an appropriate position, in the plane wall 5 of one of the two half-shells, i. e. the bearing half-shell 2, there is provided a substantially central recess 7, which forms a projection 8, on the inner side, being meant to engage under the nose-piece of the glasses frames instead of the nose, whereas the glasses are disposed with their lower side turned towards the curved wall and with their upper side in the area of the straight hinging side of the two half-shells.

The recess 7 and the corresponding protrusion 8 have a substantially cylindrical shape and terminate with an inclined and rounded bottom.

As shown in fig. 1, this protrusion 8, as well as the rear wall 4 allow to keep the glasses in a slightly inclined position, which is suitable for displaying them, the case being therefore a useful glasses displaying device.

At the center of the free edge of the arched wall of the smaller half-shell 2, there is provided an outwardly projecting cog 9. In a coincident position on the inner side of the arched wall of the larger half- shell 1, there is provided a line of parallel spaced protrusions or projections 10, which are all oriented parallel to the cog 9.

Thanks to this construction, the two half-shell

parts 1,2 fit one into the other in the closed condition, as shown in the figures and may be releasably locked in a plurality of relative progressive deeper penetration positions, as shown in figures 2 to 4. In this manner, the containing capacity of the case may be varied simply, while always maintaining an attractive look and always ensuring a good protection of the contents.

Snap after snap, the two half-shells are brought from a first closing position, in which the case has the highest housing capacity (fig. 3) to the totally closed position (fig. 4), in which the two half-shells are totally pushed the one inside the other.

Obviously, the case of the present invention may be also used for other purposes, alternative to the use for glasses.

Although the use of plastic is preferable, it is ils also possible to use other materials, such as particularly metal sheets, or similar for its fabrication.

Inside, at least on the walls of the lower half- shell 2, one or more layers of padding or lining material may be fixed.

Fig. 5 and more precisely fig. 11 show the conformation of the projections 10, which is such, that they have a markedly rounded cross section, having the shape of a cylindrical sector, particularly semielliptical or lune-shaped, with low-slope faces.

This is provided to allow the cog 9 to harmonically slip along the line of projections. The cog is also

markedly rounded, not sharply pointed and with low- slope faces.

The cog 9 may also be markedly rounded, at least on one face thereof, and in this case on that facing the closing direction, whereas the opposite face is steep.

This arrangement may be applied also to the aligned projections 10, alternatively or in combination and for faces equal to or different from those of the cog 9.

By this arrangement, the two half-shells slip through several snaps the one in relation to the other, while automatically making use of the intrinsic elasticity of the material.

Fig. 6 shows a variant embodiment of the case according to the invention which, besides having a more traditional shape, has further characteristics with respect to the line of projections 10 and to the cog 9.

Also referring to the remaining figures 7 to 12, at the front side 201 of the smaller half-shell, and outside the larger half-shell 1, when said smaller half-shell is in the totally inserted position, on said front side 102 there is provided a grasping extension or a push-button 11, projecting beyond the front side 10 of the larger half-shell when the case is in the closed condition.

This grasping extension 11 extends parallel to the free edge 201 of the larger half-shell 1 and to that 202 of the smaller one 2, and is made like a rib having a certain length.

This grasping extension is, at the same time, a push-button to be pressed inwards and backwards from the front side 102 of the smaller half-shell, i. e. acting towards disengagement or partial disengagement of the cog 9 from the line of projections 10.

Therefore, advantages are obtained from providing said grasping extension 11 in the strip substantially coinciding with the cog 9 and with the line of projections 10 on the opposite half-shell 1.

Particularly, advantages may be obtained if the cog 9, the line of projections 10 and the grasping extension 11 are provided in the coincident median strips of the peripheral front walls 101,102 of the two half-shells 1,2.

The grasping tab 11 is also advantageously an end- of-stroke abutment in the mutual insertion of the two half-shells 1,2. Said end-of-stroke abutment is advantageously assisted by projections, wings, ribs, blocks or end-of-stroke abutment extensions 12, which are provided inside the larger half-shell 1, and interact with the free front edge 202 of the smaller half-shell 2.

Said internal abutments 12 may be damped by providing that an abutment surface thereof is elastically compliant. Advantageously, this is obtained by disposing thereon a layer of elastic material, particularly foam, preferably made of the same padding lining material.

Preferably, these internal end-of-stroke abutments 12 are at least two in number and are disposed

substantially symmetrically to the median vertical plane at the two opposite end areas of the front wall 101 of the larger half-shell 1, inside it.

This embodiment allows to exert pressure to disengage or at least partially disengage the cog 9 from the line of projections 10, thanks to the elastic deformability of the walls 102, in this case of the smaller half-shell 2, since, thanks to the grasping extension 11, it is possible to move the cog 9 and the line of projections 10 slightly apart from each other, thereby providing softer opening and closing movements, when the cog 9 is slipped all through the line of projections 10.

In this case, both the cog 9 and the aligned projections 10 are made with much steeper faces 109, 110 (see figs. 10 and 12) at least at their base, whereas they are chamfered, arched and rounded, at the apices 209,210 of the cog 9 and of the projections 10, with surfaces whose radius is constant or progressively decreasing towards the apex of the cog 9 and of the projections 10. The depth of the cogs 9 is also greater and their steeper faces allow to provide shorter distances between the projections 10 and therefore a greater number of cogs all through the linear length of the line, hence a greater number of intermediate positions.

The conformation of the faces may also be asymmetrical, like in the previous embodiment, either for the cog 9 only, or for the projections only, or in such a way as to assist the reciprocal slipping motion

of the cog 9 and of the line of projections 10 in one of the two case closing or opening directions. The asymmetries may be applied to identical or opposite faces of the cog 9 and of the projections 10.

Thanks to the particular construction of these cogs 9 and projections 10, a stronger engagement force is ensured in the closed positions, particularly in the positions other than the penetration end-of-stroke. The grasping extension 11 allows to partially move the line of projections 10 apart from the cog 9, at least to a partial extent, such that the aligned projections 10 and the cog 9 can cooperate by their respective rounded parts 209,210, thereby obtaining a more harmonic and easier slipping motion of the two half-shells from the closed to the opening positions.

As disclosed above, this movement of the cog 9 apart from the line of projections 10 towards partial disengagement therefrom may occur when the user presses the grasping extension 11 which acts as a push-button, thanks to the intrinsic elasticity of the material.

The elasticity and the compliance of the wall region associated to the cog 9 and to the grasping extension 11 or to the push-button may be calibrated by any method, and without weighing heavily on production costs. These arrangements may comprise the provision of a lower wall thickness on the part of the front wall 102 of the half-shell 2 where the cog 9 and the grasping extension 11 or the push-button are provided.

Alternatively, said wall region may be connected to the rest of the wall 102 by a hinging zone or line,

made through a wall weakening or thinning line provided at said hinging zone or line.

A further variant may consist in that, by providing co-injection molds, the wall region associated to the cog 9 or to the grasping extension 11, or the hinging zone or line are made of different materials, with different deformability and elasticity characteristics, during the same molding process for the whole case.

In order to be able to retain the larger half- shell, without deforming it under pressure so as to partially reduce the moving apart action caused by the inward pressure of the grasping extension 11 or of the push-button associated to the smaller half-shell 2, it is also possible to calibrate the elasticity of the larger half-shell 1, at least in the region of the line of projections 10 in such a way that it is less deformable than the corresponding region of the smaller half-shell 2. Also in this case, this may be provided by means of any stiffening arrangements, such as a thicker wall at least in the region o. f the line of projections, or through the whole front wall 101 of the larger half-shell 1 of the larger half-shell, the provision of internal or external stiffeners like ribs, or else, the co-injection production of said region from a different material, for example less flexible of said region.

Although the above description relates to the larger half-shell 1 bearing the line of projections 10 and the smaller half-shell 2 bearing the cog 9 with the

grasping extension 11 or the push-button, the above arrangements and advantages are obtained in the same way if the line of projections 10 is alternatively provided in combination with the grasping extension 11 or the push-button on the smaller half-shell 2 and the cog 9 is provided on the larger half-shell 1.

It is also possible to provide an additional line of projections and an associated cog at another location of the front walls of the half-shells, for example two lines of projections 10, each with its corresponding cog 9, which are disposed symmetrically with respect to a median transverse point of the case.

The invention is not intended to be limited to the embodiments described and illustrated herein, but may be greatly varied, especially as regards construction.

According to a possible variant, instead of one single cog 9, interacting with a line of projections 10, there may be provided a line of cogs 9 similar to the line of projections 10 and interacting therewith. This line of cogs may be composed of at least two adjacent cogs 9.

In this way, particularly when no means are provided to disengage at least partially the cogs 9 from the line of projections 10, the profiles of the cogs and of the projections may be further flattened, i. e. provided with even less steep faces.

A further variant embodiment, shown in detail, provides lens-or dome-shaped elements, such as buttons or similar, having a circular or ovoidal or elliptical plan, instead of the cog/s and/or of the projections on the two half-shells. In this case, as shown in figure

13 with reference to an elliptical plan, both the projections and the cog protrude. Conversely, in the case of fig. 14, in which a tooth having a circular plan is shown, said projections consist of complementary cavities 10'or depressions formed in the wall of their respective half-shell. These two constructions provide the advantage that a sufficient locking effect is ensured in the reciprocal position of the two half-shells, a softer relative movement being also provided when the cog slips along the line of projections or cavities. The embodiment with cavities provides a lower material consumption and manufacturing advantages, as compared with the embodiment of fig. 13.

For both embodiments, the curvature of the cog and of the projections or cavities, particularly as considered in the slipping direction of the cog through the line of projections or cavities, may be either constant or variable according to the desired higher or lower mutual engagement force, or to the softer or harder mutual slipping motion of the two half-shells through the different closing positions. The curvature transverse to the slipping direction may also affect to a certain extent the joint resistance and the slipping softness.

All this without departure from the guiding principle of the invention, disclosed above and claimed below.