WO1998012508A1

WO1998012508A1 - Pointer, in particular for a motor vehicle dashboard

Info

Publication number: WO1998012508A1
Application number: PCT/FR1997/001667
Authority: WO
Inventors: Pascal Guirauton; Pascal Garreau
Original assignee: Magneti Marelli France
Priority date: 1996-09-23
Filing date: 1997-09-22
Publication date: 1998-03-26
Also published as: AR008477A1; FR2753790A1; FR2753790B1

Abstract

The invention concerns a pointer, in particular for a motor vehicle dashboard, comprising a hub (110) adapted to be fixed on the output shaft of drive means and a transversal index hand (150), made of an optical conductive material, characterised in that the hub (110) is arranged as a lighting outlet, and the index hand (150) comprises in line with the hub (110), means (170) for directly returning towards the body of the index hand (150) part of the light received from the hub (110), and at least a secondary cavity (180. 190) forming filter and diaphragm, such that the pointer has from moulding a homogeneous brightness over its whole length, without any added insert.

Description

NEEDLE, ESPECIALLY FOR A DASHBOARD OF A MOTOR VEHICLE

The present invention relates to the field of illuminated needles The present invention finds in particular, but not exclusively, application in dashboards of motor vehicles

Many needles comprising a bar or index in optically conductive material, associated with at least one light source have been proposed. In these needles, the light emitted by the source is injected into the bar and guided therein. Light diffuses from the bar, so that the needles are lit for an observer. These provisions facilitate in particular the observation of the hands when the ambient lighting is insufficient.

We can for example refer to documents DE-A-33 00 270 and DE-A-34 25 029 which describe such known needles. Attempts have been made for many years to improve the known needles in order to obtain a practically uniform luminance. over most of the length of the needles However, the results obtained so far are not entirely satisfactory. Indeed, on most of the known needles, zones of high luminance and zones of lower luminance are observed. Furthermore, some of the known needles prove to be quite complex to manufacture, requiring in particular different inserts to limit the differences in luminance over the length of the needles

The present invention now aims to improve the known lit needles. The main object of the present invention is to improve the homogeneity of the luminance on needles lit over their entire length.

This object is achieved according to the present invention by means of a needle comprising a hub adapted to be fixed on the output shaft of a drive means and a transverse index, made of optically conductive material, characterized in that the hub is arranged in light socket, and that the index comprises on the one hand, facing the hub, means for direct return to the body of the index of part of the light received from the hub, and on the other hand at least one auxiliary cavity forming a filter and diaphragm with respect to the light rays coming from of the hub, so that the needle has molding uniformity in luminance over its entire length, without the addition of an insert.

Other characteristics, aims and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings, given by way of nonlimiting examples, and in which:

FIG. 1 represents a schematic perspective view of a needle body according to a first embodiment of the present invention,

FIG. 2 represents a view in longitudinal section of this needle according to the cutting plane referenced II-II in FIG. 3, - FIG. 3 represents a top view of this needle,

FIGS. 4, 5 and 6 represent three views in cross section of the needle according to the section planes illustrated IV-IV, V-V and VI-VI in FIG. 3,

- Figure 7 shows a perspective view of a needle cap according to the present invention intended to be associated with this needle body, - Figure 8 shows a schematic perspective view of a conforming needle body to a second embodiment of the present invention,

FIG. 9 represents a view in longitudinal section of this needle according to the cutting plane referenced IX-IX in FIG. 10,

- Figure 10 shows a top view of this needle, - Figures 1 1 and 12 show two views in cross section of the needle according to the sectional planes illustrated XI-XI and XII-XII in Figure 10, and

- Figure 13 shows a perspective view of a needle cap according to the present invention, intended to be associated with the needle body of this second embodiment. As can be seen on the comparative examination of FIGS. 1 to 7 and 8 to 13, the needle conforming to the characteristics of the present invention can be produced in different sizes, the invention not being moreover limited to the embodiments individuals thus represented.

According to the invention, the needle essentially comprises a needle body 100 consisting of an optical conductive element, and of a cap 200 made of optically opaque material.

The needle has a longitudinal plane of symmetry which coincides with the section plane II of FIG. 2, illustrated in FIG. 3. The needle body 100 is itself formed by a hub 110 and an index 150.

The hub 1 10 is designed to be linked, preferably driven, on the output shaft of a conventional drive means, such as an Iogometer or a stepper motor.

It is formed of a generally cylindrical barrel 1 12 centered on the axis of rotation O-O of the needle.

The base surface 120 of the barrel 1 10, opposite the index 150, is planar and perpendicular to the axis of rotation O-O of the needle. It serves as an entry surface for the light emitted by underlying light sources.

These light sources can be the subject of numerous variants of conventional embodiments per se. They may, for example, be filament sources or light-emitting diodes. It will be noted that the light sources cannot be placed on the axis of rotation of the needle, due to the presence of the drive means. Several light sources are thus provided distributed around the axis of rotation of the needle.

The barrel 1 12 has a central cylindrical blind bore 1 14, by which the hub can be driven on the drive shaft.

More precisely still, preferably the external casing of the barrel 1 12 is generally frustoconical, flared towards the index, or tapered towards the end of the barrel 1 12 to facilitate demolding of the hub 1 10.

In addition the barrel 1 12 is provided with two planes or flats 1 16, 1 18 parallel to each other, diametrically opposite and respectively on either side of the plane of symmetry. These planes 1 16, 1 18 reinforce the return of the light injected at the base 120 of the hub 1 10, towards the index 150 superimposed.

The index 150 has the general shape of an elongated bar which extends perpendicular to the axis O-O of the hub 110.

In the appended figures, the upper surface of the index 150, directed towards an observer, is referenced 152, 154 its lower surface, and 156, 158 its lateral flanks.

As can be seen in the appended figures, in particular in Figures 1, 2, 3 and 8, 9, 10, preferably the index 150 extends asymmetrically on either side of the hub 1 10.

The heel of the index 150, of shorter length, is referenced 151. The upper surface 152 of the index 150 is preferably formed of a straight generator perpendicular to the plane of symmetry, as can be seen in FIGS. 5, 6 and 7. However as a variant, this upper surface 152 can be delimited by a generator curved or polygonal. Furthermore, in the plane of symmetry, the upper surface 152 is curved outwardly convex as seen in FIG. 2. It preferably responds to a generally cylindrical surface of revolution around an axis perpendicular to the plane of symmetry and whose radius is adapted as a function of the length of the index 150.

If necessary, this upper surface 152 can be provided with a white or colored coating at least partially translucent, for example in the form of a paint, defining the external appearance of the needle.

The lower surface 154 plays only a secondary role in guiding the light. In a manner comparable to the upper surface 152, it is preferably delimited by a rectilinear generator perpendicular to the plane of symmetry, as can be seen in FIG. 6. However as a variant, this lower surface 154 can also be delimited by a curved or polygonal generator . Furthermore, in the plane of symmetry, the lower surface 154 is preferably rectilinear and therefore planar as can be seen in FIG. 2. However as a variant, this lower surface 154 could be at least slightly curved in the plane of symmetry, depending in particular on the design sought.

If necessary, this lower surface 154 may be provided with an opaque coating, for example colored, or even optically opaque.

It will also be noted that the lower surface 154 is preferably provided at its rear end with a step 155 making it possible to secure the cap 200.

The lateral surfaces 156 and 158 of the index are generally flat and converge towards the tip of the index 150, as can be seen in FIGS. 3 and 10, so that the index appears at least slightly tapered.

However, as can be seen in FIGS. 1 and 8, preferably the index 150 has a lateral allowance 160 opposite the hub 1 10.

The function of this extra thickness 160 will be explained below.

The lateral surfaces of this extra thickness 160 are referenced 161 and 165. They are parallel to each other. More precisely still, as can be seen in FIGS. 1 and 8, the extra thickness 160 and the corresponding lateral surfaces 161 and 165 do not extend over the entire height of the index 150, but only over part of it, from the lower surface 154. Thus the upper edge 162 of these lateral surfaces 161 and 165 is set back from the upper surface 152.

The front edge 163 of these lateral surfaces 161 and 165 may be generally rectilinear and parallel to the axis O-O, preferably being rounded at its junction zone with the upper edge 162.

On the other hand, the rear edge 164 of these lateral surfaces 161 and 165 is preferably at least partially oblique, for example of the order of 45 °, relative to the axis O-O.

In addition at their rear end, the lateral surfaces 156 and 158 are preferably curved convex to define a rounded heel 151, for example in the form of a cylindrical cap centered on an axis parallel to the axis OO and situated in the plane of symmetry, as seen in Figures 3 and 10 especially for design purposes.

The index 150 essentially comprises a return structure 170 opposite the hub 110 and at least one filter 180.

More precisely, according to the first embodiment illustrated in FIGS. 1 to 7, two filters 180 and 190 are provided located respectively in front and in the rear of this return structure 170.

However, the second embodiment illustrated in Figures 8 to 13 has only a filter 180 in front of the return structure 170 because its heel 151 has a very short length. The return structure 170 is defined by a chamber 171 formed in the index 150. The chamber 171 has a section, considered transversely to the plane of symmetry, of rectangular outline. Its main surfaces 172 and 173 perpendicular to the plane of symmetry are planar, generally parallel to each other, and inclined on the order of 45 ° relative to the axis O-O. These surfaces 172 and 173 converge towards the upper surface 152 in proximity to the tip of the index 150.

The surface 172 closest to the hub 110, and which consequently receives the light coming from the hub 110, has a mirror polish. This surface 172 ensures the reflection of the rays arriving from the hub 1 10 with a parallel incidence at the axis OO, towards the tip of the index finger, more precisely in the direction of the upper surface 152 of the index finger

It will be noted that this chamber 171 does not open laterally on the surfaces 161 and 165, to guarantee good needle stiffness. This is the main function of the extra thickness 160

It also does not lead to the upper surface 152, as can be seen in FIG. 2 The bottom 174 of the chamber 171 located at a distance from the upper surface 152 is preferably parallel to the latter

In contrast, the chamber 171 opens onto the lower surface 154, behind the hub 1 10

It will also be noted that preferably the chamber 171 does not extend over the entire diameter of the hub 1 10, but is interrupted before the most front end of this hub 1 10

According to the first embodiment of Figures 1 to 7, the deflection surface 172 thus covers in length about 93% of the diameter of the hub 1 10, while according to the second embodiment of Figures 8 to 13, the deflection surface 172 covers approximately 60% in length of the hub diameter 1 10

The lower surface 172 of the chamber 171 essentially plays a role of reflector The upper surface 173 of this chamber plays on the contrary essentially a role of filter by letting diffuse part of the light which it receives towards the heel 151 of the needle and towards the upper surface 152, in line with the hub 1 10

Chamber 171 is defined by a suitable drawer in the mold

The filters 180 and 190 are in turn forms of cavities 181 and 191 which open laterally on the surfaces 156 and 158

They are preferably cavities 181 and 191 of rectangular section whose main faces are parallel to the lower surface 154

Typically but not limited to, the cavities 181 and 191 have a length of the order of 3mm and a thickness of the order of 0.8mm These cavities 181 and 191 which form horizontal references, obscure the direct radius and return a part of the light energy which they receive towards the ends of the index, thereby attenuating the luminance peaks which would otherwise appear on the upper surface 152 The cavities 181 and 191 cover the chamber 171 in a projection on a plane orthogonal to the axis OO. Thus the spokes which come from the hub 110, parallel to the axis OO, cannot directly reach the upper surface 152 It will also be noted that to avoid a peak in luminance opposite the hub 1 10, preferably the free passage for the light, in the index 150, opposite the hub 1 10, is limited by opaque tongues 240 integral with the cap 200 engaged in two slots side 140 re-aligned in the index 150 These lights 140 are visible in particular in FIGS. 1, 4 to 6, 8, 1 1 and 12

They are formed above the extra thickness 160, that is to say between the upper edge 162 of the latter and the upper surface 152 The two openings 140 open respectively on the lateral surfaces 156 and 158

They preferably have a curved contour, in a projection on the plane of symmetry, thus following the curved contour of the upper surface 152

In a nonlimiting manner, the two slots 140, of the same depth, typically obscure approximately 1/3 of the width of the index 150 In other words, each of the slots 140 preferably has a depth substantially equal to 1/6 of the width of the index finger 150

According to the first embodiment of Figures 1 to 7, each lumen 140 has its ends superposed respectively on the cavities 181 and 191

Preferably the lights 140 are adapted to return downwards the light they receive. To this end their lower surface, that is to say directed towards the lower surface 154, is inclined relative to this lower surface 154, for example by 45 °, diverging with respect to this lower surface 154 towards the interior of the 'index. The lights 140 preferably have a section of triangular shape. However, the invention is not limited to this particular shape.

The lights 140 and the cavities 181 and 1 1 are also defined by suitable drawers in the mold

The cap 200 can be the subject of numerous embodiments

It is preferably made of a black thermoplastic material It is suitable for laterally surrounding the index finger at the heel 151 and facing the hub 1 10 and also cover the protuberances of the extra thickness 160.

It is preferably formed of a cylindrical skirt 210 surmounted by a flat upper wall 220.

The skirt 210 and the wall 220 can define a rear projection corresponding to the heel 151 (see the first embodiment of FIGS. 1 to 7).

The junction border between the cylindrical skirt 210 and the upper wall 220 can be truncated, as can be seen in FIGS. 7 and 13. The upper wall 220 and part of the height of a front sector of the skirt 210 has a slot 230 complementary to the width of the index 150 to receive the latter.

In addition, the cap has different internal fins 250 which ensure the stiffness of the cap 200. The abovementioned tongues 240 which penetrate into the slots 140 of the index 150 are preferably molded on the lower surface of the wall 220.

To assemble the cap 200 on the needle body 100, simply engage the index 150 by the tip and through the interior of the cap 200 into the slot 230 and push the index 150 to engage the tabs 240 of the cap in the slots 140. The cap 200 is then immobilized automatically mechanically without the need to resort to additional fixing means, such as gluing or the like.

It will be noted that the joint plane of the molding shells of the index 150 preferably coincides with the curved edges defined between the upper surface 152 and the lateral flanks 156, 158.

This arrangement makes it possible to avoid any burr or irregularity on the optically active surfaces. In particular, the upper surface 152 visible to an observer is free from any defect.

Preferably the needle body 100 is made of one of the following materials:

Of course the present invention is not limited to the embodiments which have just been described but extends to all variants in accordance with its spirit. The optical means according to the present invention, defined in the index 150, in particular the return by the surface 172, the filter by the cavities 180 and

190 and the partial concealment by the tongues 240 introduced into the slots 140, make it possible to obtain lighting that is at least substantially homogeneous over the entire length of the needle.

It will further be noted that the present invention allows an economical embodiment insofar as the index 150 can be produced by simple molding, without requiring the use of insert or equivalent means. And it suffices to mechanically engage the cap 200 on the needle body 100 to obtain a ready-to-use needle.

Claims

1. Needle, in particular for a dashboard of a motor vehicle, comprising a hub (110) adapted to be fixed on the output shaft of a drive means and a transverse index (150), made of optically conductive material, characterized in that the hub (1 10) is arranged in light socket, and that the index (150) comprises on the one hand, facing the hub (1 10), means (170) for direct return to the body of the index (150) of part of the light received from the hub (1 10), and on the other hand at least one auxiliary cavity (180, 190) forming a filter and diaphragm with respect to the light rays from the hub (1 10), so that the needle has molding uniformity of luminance over its entire length, without the addition of insert.

2. Needle according to claim 1, characterized in that it has a longitudinal plane of symmetry.

3. Needle according to one of claims 1 or 2, characterized in that the return structure (170) is defined by a chamber (171) formed in the index (150).

4. -Needle according to claim 3, characterized in that the chamber (171) has a section, considered transversely to the plane of symmetry, of rectangular outline, the main surfaces (12 and 173) perpendicular to the plane of symmetry are planes, generally parallel to each other, and inclined on the order of 45 ° relative to the axis of rotation (OO), the main surfaces (172 and 173) converging towards the upper surface (152) in approach to the point of the index (150).

5. Needle according to one of claims 3 or 4, characterized in that the surface (172) of the chamber (171) closest to the hub (1 10), and which therefore receives the light from the hub ( 1 10), has a mirror polish to ensure the reflection of the rays arriving from the hub (1 10) with an incidence parallel to the axis of rotation (OO), towards the tip of the index finger towards the upper surface (152 ) of it.

6. Needle according to one of claims 3 to 5, characterized in that the chamber (171) does not open laterally.

7. Needle according to one of claims 3 to 6, characterized in that the chamber (171) opens onto the lower surface (154) of the needle index (150), behind the hub (1 10) .

8. Needle according to one of claims 3 to 7, characterized in that the chamber (171) does not extend over the entire diameter of the hub (1 10), but is interrupted before the most forward end of this hub (1 10)

9. Needle according to one of claims 1 to 8, characterized in that it comprises a single auxiliary cavity (181) forming a filter in front of the direct return means (170).

10. Needle according to one of claims 1 to 8, characterized in that it comprises two auxiliary cavities (181, 191) forming a filter respectively in front and behind direct return means (170).

1 1. Needle according to one of claims 1 to 10, characterized in that each filter (180 and 190) is formed of a cavity (181 and 191) which opens laterally on the index (150).

12. Needle according to one of claims 1 to 1 1, characterized in that each filter is formed by a cavity (181 and 191) of rectangular section whose main faces are parallel to the lower surface (154) of l 'index (150).

13. Needle according to one of claims 1 1 or 12, characterized in that each cavity (181 and 191) has a length of the order of 3mm and a thickness of the order of 0.8mm.

14. Needle according to one of claims 1 to 13, characterized in that each filter (180, 190) consists of a cavity (181 and 191) which forms a horizontal reference, obscures the direct rays and returns a part of the light energy which it receives towards the ends of the index, thereby attenuating the peaks of luminance which would otherwise appear on the upper surface (152) of the index (150).

15. Needle according to one of claims 1 to 14, characterized in that each cavity (181 and 191) covers the chamber (171) constituting the return means, in a projection on a plane orthogonal to the axis of rotation (OO), so that the spokes which come from the hub (110), parallel to the axis (OO), cannot directly reach the upper surface (152) of the index (150).

16. Needle according to one of claims 1 to 15, characterized in that the index (150) is provided with two lateral lights (140) which open out respectively on the lateral surfaces (156 and 158) and receive tongues (240) integral with an opaque cap (200).

17. Needle according to claim 16, characterized in that the apertures (140) have a curved outline, in a projection on the plane of symmetry, thus following the curved outline of the upper surface (152) of the index finger (150 ).

18. Needle according to one of claims 16 or 17, characterized in that each of the lumens (140) has a depth substantially equal to 1/6 of the width of the index (150).

19. Needle according to one of claims 16 to 18, characterized in that the lights (140) are formed opposite the hub (1 10) and are adapted to return downwards the light they receive from it- this.

20. -A needle according to one of claims 16 to 19, characterized in that the lower surface of the tongues (140) is inclined relative to the lower surface (154) of the index, for example by 45 °, diverging with respect to this lower surface (154) of the index towards the interior of the index.

21. Needle according to one of claims 1 to 20, characterized in that the hub (1 10) is formed from a barrel (112) generally cylindrical centered on the axis of rotation (OO) of the needle, whose base surface (120), opposite the index (150), is planar and perpendicular to the axis of rotation (OO) of the needle to serve as an entry surface for the light emitted by light sources underlying.

22. Needle according to one of claims 1 to 21, characterized in that the hub (1 10) is provided with two planes or flats (1 16, 1 18) parallel to each other, diametrically opposite and respectively on the part and d another of a plane of symmetry.

23. Needle according to one of claims 1 to 22, characterized in that the upper surface (152) of the index (150) is formed of a rectilinear generatrix perpendicular to the plane of symmetry, and moreover in the plane of symmetry, the upper surface (152) is curved outwardly convex, preferably being cylindrical of revolution about an axis perpendicular to the plane of symmetry.

24. Needle according to one of claims 1 to 23, characterized in that the upper surface (152) of the index finger is provided with a white or colored coating at least partially translucent.

25. Needle according to one of claims l to 24, characterized in that the index 150 has a lateral allowance (160) opposite the hub (1 10).

26. Needle according to one of claims 1 to 25, characterized in that it further comprises a cap (200) of opaque covering adapted to at least partially surround the index finger (150)

27. Needle according to one of claims 1 to 26, characterized in that it comprises a covering cap (200) formed of a cylindrical skirt (210) surmounted by a flat upper wall (220), the upper wall (220) and part of the height of a front sector of the skirt (210) having a slot (230) complementary to the width of the index (150) to receive the latter.

28. Needle according to claims 16 and 27 taken in combination, characterized in that the tongues (240) are molded on the inner surface of the upper wall (220) of the cap (200).