EP0186804B1 - Wrist-mounted electronic device - Google Patents

Abstract

The connection arrangement of this invention includes one or several sets of electrical contacts, respectively within the case of an electronic appliance and the bracelet thereof. These contacts are separable by virtue of being associated with elastic latching means. Moreover they are surrounded by a complementary abutment surfaces which protect them from all damaging influence coming from the exterior (in particular that resulting from corrosive substances which may be exuded by the wrist). These surfaces are firmly applied to one another by the latching force of the contacts. The invention may be applied in particular to any timepiece having a bracelet.

Description

The present invention relates to electronic devices intended to be worn on the wrist of a user. More specifically, the invention relates to an electrical junction device between the parts of a circuit located respectively in the case and the bracelet of an electronic device intended to be worn on the wrist, in which, in each electrical path between said parts, is inserted a set of separable conjugate contacts but maintained applied one on the other, each set of contacts having at least partially a symmetry of revolution defining an axis.

Such a joining device is described in document GB-A-1 555 848. This device comprises a block provided with holes in which are placed contact springs. The bracelet provided with conductors has one end which is received inside the case and which is in contact with one face of the block so that each spring can come into contact with a conductor of the bracelet. The opposite face of the block is in contact with an insulating part in which there are complementary conductors leading to the internal circuits of the electronic device. The case thereof is in two parts assembled together, this assembly making it possible to tighten the block with the springs between the end of the bracelet and the insulating part.

This arrangement has several drawbacks. Thus, it cannot be easily disassembled, because to remove the bracelet, it is necessary to disassemble the case. In addition, this disassembly carried out, we are confronted with several spare parts, in particular the small contact springs which risk being lost, for example. Finally, the contact pressure is dependent on the force of the springs and the degree of tightening with which the two parts of the box are assembled.

The invention aims to remedy these drawbacks.

It therefore relates to a device of the type defined above which is characterized in that the contacts are applied to one another by a latching force directed along said axis and in that they are surrounded by two complementary abutment surfaces provided one on the bracelet and the other on the case and applied one to the other by virtue of the presence of said snap-on force to protect the contacts from harmful influences coming from the outside, and in that one of the contacts of the contact set is a conductive pin anchored in the box or the bracelet and penetrating into an opening of the bracelet or respectively of the box, the latter or the latter and said conductive pin having complementary annular surfaces to ensure the latching.

Thanks to these characteristics, the bracelet can easily be disassembled and reassembled without there being a risk of poor contact or deterioration in the quality of the seal protecting the contacts against harmful effects coming from the outside.

It is thus possible to always ensure perfect sealing of the case and total insulation of the electrical contacts from the outside. This latter property of the junction device according to the invention therefore protects the contacts from any harmful influence liable to cause corrosion which can be caused for example by the proximity of the skin of the user. The longevity of the contacts is therefore ensured.

From document FR-A-2 284149, a watch with plug-in functional modules is known in which the modules are assembled by elements ensuring elastic snap-fastening. However, in this case, the pressure of the electrical contact between two modules is not directed according to the latching force so that the good quality of the electrical contact cannot be guaranteed especially after disassembly and reassembly of the watch.

Furthermore, from document EP-A-0 125 930, a connection device for a watch is known, in which the bracelet comprises an antenna formed by a conductive tape. On this ribbon comes to bear a contact piece under the action of a locking system of the watch case which is articulated on a strand of the bracelet. In this device, there is therefore no set of contacts associated with an elastic latching arrangement whose latching force acts in the direction of a better contact pressure.

Document US-A-3 977 176 describes a watch whose battery is housed in a case separate from a second case comprising the timepiece. Contact tabs provide the connection between the two elements. There is no latching system in this arrangement and the two elements cannot be separated from each other until the second housing has been removed.

• - la figure 1 est une vue en perspective d'un dispositif de jonction électrique suivant l'invention conformément au mode de réalisation préféré;
• - la figure 2 est une vue en coupe axiale d'un dispositif de jonction suivant l'invention correspondant à celui de la figure 1;
• - la figure 2A montre une vue en coupe agrandie du dispositif de jonction;
• - la figure 3 est une vue en plan de l'une des languettes du bracelet, montrant notamment les pistes conductrices destinées à être reliées aux dispositifs de jonction représentés sur les figures 1 et 2;
• - les figures 4 et 5 montrent, par des vues en coupe axiale, deux autres modes de réalisation de l'invention;
• - la figure 6 est une vue partielle en perspective d'une variante du dispositif de jonction suivant l'invention.

The invention will be better understood on reading the description which follows of several embodiments, this description being given solely by way of example and made with reference to the appended drawings in which:

• - Figure 1 is a perspective view of an electrical junction device according to the invention in accordance with the preferred embodiment;
• - Figure 2 is an axial sectional view of a joining device according to the invention corresponding to that of Figure 1;
• - Figure 2A shows an enlarged sectional view of the joining device;
• - Figure 3 is a plan view of one of the tabs of the bracelet, showing in particular the conductive tracks intended to be connected to the junction devices shown in Figures 1 and 2;
• - Figures 4 and 5 show, in axial sectional views, two other embodiments of the invention;
• - Figure 6 is a partial perspective view of a variant of the joining device according to the invention.

Without this being in any way limiting of the invention described, the example which will be described in referring to FIGS. 1, 2 and 2A relates to a box B associated with a bracelet BR between which several electrical paths must be established, at the level of the separation between these two elements, by junction devices according to the invention, these devices being designated as a whole by the reference 1. The box B contains the electrical or electromechanical circuit of a timepiece, but it should be emphasized that the invention applies in all cases where an electronic device is associated with a bracelet which includes one or more components to be associated with the circuit which is located in the case B.

In FIG. 2, it can be seen that this box contains a printed electrical circuit CI provided with an integrated circuit (not shown) and a display device DA, the box being closed by a glass G.

The junction device comprises sets of contacts 2 composed of a rigid conductive element 3 and of an elastic conductive element 4. The first of these contacts is here a conductive pin of generally cylindrical shape with an axis X-X.

This pin has an outer surface composed of several portions which are, seen from top to bottom in FIG. 2A, a bearing 5 separated from a bearing 6 by a radial shoulder 7, a frustoconical portion 8 followed by a cylindrical portion 9, a bearing surface 10 separated from the cylindrical portion 9 by a shoulder 11, a portion 12 in the form of a "diabolo" having in particular two inclined surfaces 12a and 12b between which is provided a cylindrical surface 12c, a cylindrical portion 13 and finally a point 14 of general conical shape.

This relatively tormented shape of the outer surface of the pin is intended, in the area where this pin is fixed in the housing B, to ensure an impeccable seal, in order to isolate the exterior of the interior cavity thereof. Of course, the housing has a hole 15 with surface portions complementary to those of the corresponding part of the pin, but which it is unnecessary to describe in detail here. It suffices to note that the final shape of the hole 15 of the housing through which the pin 3 extends is obtained during the positioning thereof which, preferably, is carried out by the application of ultrasound. Optionally, this seal can be perfected by pouring a small amount of a polymerizable material around the top of the pin 3, after the pin has been put in place, this material being sucked by capillary action around the surface 5 in order to close all interstices. possibly remaining around the body of the pin inserted in the housing B.

The portions 12a, 12b and 12c are intended to ensure the joining by elastic snap-fastening of the joining device. To this end, the end of the bracelet BR is shaped so as to define a cavity 16, into which the lower part of the pin 3 can penetrate.

Before examining this part of the joining device in more detail, it is useful to refer first to Figures 1 and 3 which show the construction of the bracelet.

In the example described here, the part of the junction device housed in the bracelet comprises four function keys generally designated by the references Ta to Td which can trigger in the circuit CI the functions "Watch", "Alarm", "Chronograph" and "Timer".

The half-bracelet shown has two strips 17a and 17b made of a flexible plastic material, the strip 17b fitting into a recess 18 provided in the end part of the strip 17a close to the housing B. This recess has a thickness which is roughly equal to half the total thickness of the strip 17a. This is made integral with the strip 17b, by gluing for example, an adhesive being provided for this purpose (in 19) over the entire periphery of the strip 17b.

This strip 17b is also provided with a set of conductors 20 which can be affixed thereto by screen printing for example. This set of conductors is provided on the face of the strip 17b facing the strip 17a.

FIG. 3 shows that the set of conductors defines four fixed contacts each produced in the form of two combs 21 a to 21 d respectively associated with mobile contacts formed by metallizations 22 (only the metallization of the Td key appearing clearly on the figure 1). Each set of a fixed contact and a movable contact forms a switch which is closed when, by finger pressure, the zone corresponding to a given key is deformed and the metallization 22 pressed on the corresponding nested combs. To increase the flexibility of the strip 17a in the areas where the keys Ta to Td are provided, there is provided at the location of each of these keys a cavity 23 opening towards the strip 17b and on the bottom of which is provided metallization 22.

In FIG. 3, it is also clearly seen that the pairs of combs 21a to 21d are connected to conductors 24a to 24e, it being understood that the conductor 24a is common to all the pairs of combs 21a to 21d. Each of the conductors 24a to 24e extends towards the end of the strip 17b to end in a terminal 25.

It is therefore understood that when an area of the strip 17a corresponding to one of the keys Ta to Td is pressed, the metallization 22 connects to one another the two combs corresponding to this key, which establishes a short circuit between the conductor 24a on the one hand and one of the conductors 24b to 24e on the other hand, the two corresponding terminals 25 are then connected to each other.

The strip 17a also comprises a thickened zone 26, of convex shape, in which is provided a transverse opening 27 intended to receive a pin 28 by means of which the bracelet is articulated to the case B, the latter comprising for this purpose a shape adapted to the boss 26 (see in particular Figure 2). It should be noted that the articulation between the case B and the bracelet BR is only partially shown, its shape being moreover conventional.

In the area of the strip 17a located beyond the boss 26, that is to say at the end of this lamella, there are provided the elements which ensure the snap-fastening of the junction device and to examine these elements we will again refer to FIG. 2.

As in the embodiment shown, there are five terminals 25 to be connected to the circuit CI in the housing B, it is obvious that five contact sets should be provided.

Each of these devices therefore comprises, centered on the axis XX an annular rib 29 having a frustoconical outer surface 30, to which corresponds a frustoconical complementary surface 31 provided in the housing B and which therefore constitutes a portion of the wall of the hole 15 of this one. We will see later that these two surfaces are of great importance for achieving the protection of the contacts of each of the junction devices.

The annular rib 29 thus delimits the cavity 16 described above, the mouth of which is formed by a flange 32. The radial section of the latter has a V shape, the point of which is directed towards the axis X-X. Preferably, one of the branches of this V, that is to say that which is closest to the free end of the pin 3, is inclined relative to the radial plane passing through the tip of the V by 30 °, the other branch being 60 °. These dimensions also correspond to the inclinations of the surfaces 12a and 12b of the pin 3.

Therefore it is understood that, given the fact that the portion 13 of the pin 3 has a diameter significantly greater than the smallest diameter of the flange 32, the insertion of the pin 3 in the cavity 16 first produces a deformation of the rib 32 at the passage of the portion 13, then an elastic snap-fastening when this flange 32 enters the groove delimited by the portions 12a to 12c of the pin 3. However, the dimensions of the parts have been chosen such that the surfaces 30 and 31 are applied closely to each other, the rib 29 being pulled axially upwards (force F indicated in FIG. 2). To this is added that the frustoconical surfaces 30 and 31 shrink in a direction which corresponds to that in which the latching force acts. Furthermore, since the contact clearances are provided in a zone of the bracelet which is situated at one end which extends beyond the articulation of the bracelet with respect to its main strand, said force is in a way increased by a force. which results from the couple created around the axis 27 by the natural curvature of the bracelet when the electronic device is worn on the wrist. It therefore follows that the cavity 16 in which the electrical contact is established is perfectly isolated from the outside.

Figures 1 and 2 clearly show that the terminals 25 are in contact with a connection block 33 which constitutes an elastomeric connector composed of alternately conductive and insulating zones and made of a flexible material such as silicone, the conductive zones being charged by carbon particles. It is therefore understood that these conductive zones can establish an electrical connection between the terminals 25 and the ends of the pins 3, the latter slightly deforming the contact block 33 where they are applied to the latter. It should be noted that the elasticity of the block 33 contributes to a good contact pressure thanks to the deformation that this block undergoes during the assembly of the junction devices.

It should be noted that the abutment surfaces 30 and 31 have a frustoconical shape coaxial with the axis XX, their conicity being rotated so that they are applied to one another with an even greater force that the holding force of the pin in the cavity 16 is greater.

We will now describe several other possible embodiments of the invention with particular reference to Figures 4 to 8. In these figures, the identical or equivalent elements of the joining device with respect to the previous embodiment have been given the same references .

In FIG. 4, the joining device comprises conductive pins 34 whose end, instead of having a hollow profile, has a larger diameter than the rest of the pin, in order to ensure the snap-fastening in an annular groove inner 35 that has the rib 29. It is understood that this arrangement has the same effects as those resulting from the junction device described above, the surfaces 30 and 31 being applied to each other in the same way.

In the case of FIG. 5, it is an inverted arrangement in the sense that a pin 36 is provided in a conductive material which is anchored by a flange 37 in a cavity 38 formed in the rib 29 of the coverslip 17a. This pin is also immobilized by the strip 17b which, as previously described, is glued to the strip 17a. The upper part of the pin 36 has a boss 39 of circular section and of a shape roughly identical to that of the end of the pin 34 in FIG. 4, this boss being inserted in an opening 40 provided in the housing, l elastic snap being obtained by the fact that the boss 39 has a diameter greater than that of the opening 40. In this case also, the surfaces 30 and 31 formed respectively on the rib 29 of the bracelet BR and on the case B are applied one on the other by the force generated by the elastic snap. In the case of FIG. 5, the boss 39 is applied against a contact block 41 which is housed in the case instead of being in the bracelet.

The variant shown in Figure 6 differs from the previous embodiment in that the sealing surfaces 30 and 31 are not provided individually for each junction device, but on the contrary are common to all of them. To this end, a rib 50 is provided which goes around a row of holes 51 aligned along the end edge of the tongue 17a of the bracelet BR, a complementary arrangement being provided on the case B. elastic, on the contrary, is obtained individually for each pawn.

It is understood that the embodiment of the Fig. 6 can be of reverse design, that is to say with the pin on the bracelet and the rib on the case.

Finally as regards the bracelet and as can be seen in FIG. 1, the strip 17b has reinforcement zones 55 separated by transverse grooves 56 and intended to reinforce the bracelet opposite the keys Ta to Td, this in order to avoid the risk of untimely contact due to the curvature of the bracelet.

Claims (6)

1. An electrical connection arrangement between the parts (Cl; Ta to Td) of a circuit located respectively in the case (B) and the bracelet (BR) of an electronic appliance intended to be worn on the wrist, in which, in each electrical path between said parts there is inserted a set of mating contacts (3, 4) which are separable but kept applied to one another, each set of contacts (3, 4) at least partially exhibiting a rotational symmetry defining an axis (X-X), characterized in that the contacts (3, 4) are applied to one another by a latching force (F) directed along said axis (X-X) and in that they are surrounded by two complementary abutment surfaces (30, 31) one of which is provided on the bracelet (BR) and the other on the case (B) and applied to one another by virtue of the presence of said latching force (F) in order to protect the contacts from damaging influences from the exterior, and in that one of the contacts from the set of contacts is a conductive foot (3, 34; 36) anchored in the case (B) or the bracelet (BR) and penetrating into an opening in the bracelet (BR) or respectively in the case (B), the latter or the latter and said conductive foot (3, 34; 36) exhibiting complementary annular surfaces to assure the latching.

2. An arrangement according to claim 1 characterized in that said complementary abutment surfaces (30, 31) are tapered and are narrowed in a sense which corresponds to that along which the latching force (F) acts.

3. An arrangement according to either of claims 1 and 2 characterized in that the set or sets of electrical contacts (3, 4) are provided in a part of the bracelet (B) which, relative to the main strand thereof, is located beyond the pivot axis (27) around which such strand is articulated on the case (B) and in that said axis of symmetry (X-X) is perpendicular to this pivot axis.

4. An arrangement according to any of the preceding claims characterized in that one of the contacts of said set of contacts (3, 4) is a conductive foot (3; 34) mounted in a sealed manner in said case (B) whilst projecting beyond the outer surface of the latter and in that such foot coacts with an annular rib (29) arranged on the bracelet into which it penetrates to be latched thanks to the complementary annular surfaces (12a to 12c, 32) provided on the foot and the rib.

5. An arrangement according to claim 4 characterized in that the other contact of the set of contacts (3, 4) is an elastic block of conductive plastic material which is partially deformed by said foot (3) when the connection arrangement is assembled and which is electrically coupled to the part of the circuit located in the bracelet (Ta to Td, 20).

6. An arrangement according to any of the preceding claims characterized in that several contact sets being arranged in a row, said abutment surfaces (30, 31) are common to all of such contact sets (Fig. 8).

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