EP1515203B1 - Manufacturing and assembly method electrical contacts for small sized switches, in particular used in watch making - Google Patents

Description

TECHNICAL AREA

The present invention relates to a method for manufacturing and assembling electrical contacts for small-sized control members, in particular for control members used in watchmaking. The present invention relates in particular to such a method for producing a multifunctional crown rod of a timepiece or other similar electromechanical or electronic apparatus.

TECHNOLOGICAL BACKGROUND

Conventionally, the electrical contacts of control members (eg push-buttons, crown rods or the like) are designed as a movable part which can be actuated by the control member to selectively establish a connection electric with another part, usually fixed, of the electrical contact. The moving part of the electrical contact is typically made in the form of a contact blade cut from a plate of an electrically conductive material (usually a metal such as steel or copper) and bent to the desired shape. Each contact blade thus formed is then mounted and fixed in the vicinity of the control member. This operation is for example carried out by hand or according to automatic assembly processes consisting essentially of the gripping by a manipulator of the contact blade (the contact blades being typically arranged in bulk or in a strip in a feed device) and its mounting by the manipulator on its final support with which the contact blade is made integral.

As long as the contact blades are of a reasonable size and their configuration is not too complex, mounting operations are generally not a problem. However, this is not the case since the contact blades have a very small size making their individual handling difficult both by an operator and by a machine. Added to this are additional constraints, since a plurality of electrical contact blades must be mounted with a relatively high precision, some by compared to others. This is particularly the case for the manufacture and assembly of electrical contacts for multifunctional control members. In particular, multifunctional crown rods are described whose rotations and axial positions are detected and translated by means of a plurality of electrical contacts.

In the field of watchmaking documents are known US6203190 , US6146010 and US6422740 which describe control members of the electromechanical type, in particular crown rods.
In the more general field of electrical contacts suitable for cooperating with control members the document is known US4944691 . This document describes (FIGS. 9 to 13) the stamping and preforming of a metal plate to form a structure comprising electrical contact blades. When inserting an electrical control member (for example, a control circuit) these blades are actuated by the control member.
US4944691 also discloses (Figure 14) a step of positioning the plate on a support part, the accuracy of this positioning is guaranteed by tenons. Finally, a step of breaking the metal structure allows to isolate the contact blades of the base.

STATEMENT OF THE INVENTION

A general object of the present invention is to propose a solution making it possible to manufacture and mount with greater ease the electrical contacts of control members of small dimensions. The present invention aims in particular to simplify the manufacture and assembly of electrical contacts of control members used in watchmaking.

To this end, the subject of the present invention is a method for manufacturing and mounting electrical contacts for small-sized control members, the characteristics of which are set forth in claim 1.

The method thus comprises a first step of stamping and preforming a plate of an electrically conductive material to form an intermediate base plate comprising a support structure and a plurality of electrical contact blades still mechanically linked to the structure of the structure. support by a plurality of attachment points, each electric contact blade comprising a base and a flexible extension connected to the base to form the movable portion of an electrical contact operable by a control member. This first step is followed by a step of positioning the intermediate base plate on a first support part electrically insulated from the electrical contact blades, and by a step of fixing on the first support part of a second insulated support part. electrically contacting blades so that each of the electrical contact blades is held between the first and second support members by its base. Finally follows a step of breaking the plurality of attachment points connecting the plurality of electrical contact blades to the support structure so that all the electrical contact blades are made independent and electrically isolated from each other.

It will be understood that this method makes it possible to manufacture and mount with simplicity small electrical contact blades. Indeed, when positioning and fixing the electrical contact blades, the latter are still linked together by the support structure. This support structure can thus be manipulated with the electric contact blades with greater ease. On the other hand, the accuracy of the relative positioning of the various blades of electrical contact is ensured by the fact that the contact blades are still bonded together during the fixing step.

According to one embodiment, the above-mentioned method is implemented particularly for the production of a multifunction crown-pin of a timepiece. According to this exemplary embodiment, the stamping and preforming step includes the preparation of a first set of electrical contact blades for the detection of rotations of the crown rod and a second set of electrical contact blades for the detection of axial positions of the stem-crown. Preferably, the stem-crown comprises an electrically insulated end for actuating the electrical contact blades, this end comprising a first part with a non-constant radius forming a cam for the actuation of the first set of electric contact blades and a second part comprising several portions. cylindrical of different diameters for the actuation of the second set of electric contact blades.

In the context of the aforementioned embodiment, the first set of electrical contact blades advantageously comprises first and second electrical contact blades placed on either side of the crown rod, the flexible extensions of the first and second contact blades. electrical being oriented substantially perpendicular to the axis of the crown rod and offset axially relative to the stem-crown so as to translate the rotations of the stem-crown in the form of electrical signals. Similarly, the second set of electrical contact blades advantageously comprises first and second electrical contact blades placed on either side of the stem-crown, the flexible extensions of the first and second electrical contact blades being oriented substantially parallel to the axis of the crown rod and offset axially relative to the stem-crown so as to translate the axial positions of the stem-crown in the form of electrical signals.

Other advantageous embodiments are the subject of the dependent claims.

SUMMARY DESCRIPTION OF THE DRAWINGS

• la figure 1a est une vue en plan d'ensemble d'une tige-couronne multifonction comprenant un jeu de quatre contacts électriques fabriqués et montés selon un mode de mise en oeuvre de l'invention ;
• la figure 1b est une vue en plan agrandie de la figure 1a où les éléments masquant les contacts électriques ont été supprimés pour faire apparaître les lames de contact électrique actionnées par la tige-couronne ;
• la figure 2 est une vue en perspective des lames de contact électrique de la tige-couronne multifonction de la figure 1, illustrées dans une configuration avant montage où elles sont encore solidaires d'une structure de support conformée avantageusement en bande, cette bande comportant plusieurs jeux de lames de contact électrique identiques ;
• les figures 3a à 3f illustrent chronologiquement une succession d'étapes mises en oeuvre en vue de la fabrication et du montage des contacts électriques pour la réalisation de la tige-couronne multifonction de la figure 1 a.

Other features and advantages of the present invention will emerge more clearly on reading the following detailed description of embodiments of the invention given solely by way of nonlimiting examples and illustrated by the appended drawings in which:

• the figure 1a is an overall plan view of a multifunctional crown rod comprising a set of four electrical contacts manufactured and mounted according to a implementation of the invention;
• the figure 1b is an enlarged plan view of the figure 1a where the elements masking the electrical contacts have been removed to reveal the electrical contact blades actuated by the stem crown;
• the figure 2 is a perspective view of the electric contact blades of the multifunctional stem-crown of the figure 1 , illustrated in a configuration before mounting where they are still integral with a support structure advantageously formed into a strip, this strip having several sets of identical electrical contact blades;
• the Figures 3a to 3f illustrate chronologically a succession of steps implemented for the manufacture and assembly of electrical contacts for the realization of the multifunctional crown rod of the figure 1 at.

DESCRIPTION OF MODES OF IMPLEMENTATION OF THE INVENTION

The figures illustrate an example of a particular embodiment of the invention for the production of a multifunctional crown rod of a timepiece or other similar electromechanical or electronic device. As will be seen below in detail, the invention can however be implemented in the context of the manufacture and assembly of electrical contacts for other types of control members, such as pushbuttons or bodies similar operating one or more electrical contacts to translate the movement or the position of the control member. By way of example, the control member could be of a type similar to a two-axis joystick. It should therefore be noted that the invention is not limited to the sole embodiment of multifunctional crown rods as described below. Furthermore, although a particularly interesting application of the invention is the production of control members for timepieces, the invention could be applied in other fields, such as the manufacture of control organs for instruments portable electronic devices (PDAs, cell phones, etc.).

The figure 1 a is a plan view showing an overview of a multifunction crown rod. By "multifunctional stem-crown" is meant here a control member comprising a rod (designated by reference numeral 1 in the figures) that can be manipulated by the user through a ring (designated by the reference numeral 10 in the figure 1a ) integral with the rod 1 and whose direction of rotation and / or the axial positions are translated into electrical signals through a plurality of electrical contacts actuated by the rod 1. These electrical contacts are disposed and arranged in the form of a compact module generally designated by the reference numeral 2 placed at the end of the rod 1 located opposite the ring 10. The rod 1 further comprises an annular groove 3 intended to receive an O-ring (not shown) provided for sealing between the rod 1 and the box (not shown) through which the rod 1 penetrates.

In the example illustrated, the rod 1 is capable of occupying four distinct axial positions, namely a neutral position, two stable positions called "pulled" and an unstable position called "push", and can also undergo rotations in the clockwise and counter-clockwise. In the figures 1 a and 1b, the rod 1 is illustrated in its extreme drawn position.

The four axial positions and the direction of rotation of the rod 1 are translated into electrical signals through two sets of independent electrical contacts. The first set of electrical contacts comprises in particular two electric contact blades 21, 22 to translate the direction of rotation of the rod 1, each electrical contact blade 21, 22 delivering an electrical signal composed of an alternation of binary logic levels (states "activated" or "deactivated") making it possible to distinguish between the two directions of rotation of the rod 1. The second set of electrical contacts comprises in particular two electric contact blades 23, 24 to translate the four axial positions of the rod 1 , each electrical contact blade 23, 24 delivering a binary logic type electrical signal which is a function of the axial position of the rod.

The end of the rod 1 and the electrical contact blades 21 to 24 are covered by a cover 7 made of an electrically insulating material (a part advantageously made by molding a plastic) and which is secured to a support plate generally designated by the reference numeral 4. The upper face 7a of the cover 7 comprises a recess 70 of particular shape forming a housing for an open spring element 9. This spring element 9 has a particular bent shape, known from the prior art, adapted to maintain the rod 1 in its three stable axial positions. This spring 9 is conventionally arranged to cooperate with three adjacent annular grooves formed on the body of the rod 1 and separated by beads. These annular grooves and beads are not referenced but appear clearly on the figure 1 b. The spring 9 thus comprises two free ends 9a, 9b (oriented substantially perpendicular to the plane of the illustrations of the figures 1 a and 1b) which extend inside the module 2, on either side of the rod 1. During an axial displacement of the rod 1, the free ends 9a and 9b of the spring 9 are spread by sliding on the beads before closing on one of the annular grooves of the rod 1.

The aforementioned support plate 4 here consists of two parts superimposed. A first lower part (or base plate) 5 is made of an electrically conductive material and is intended to be brought to a specific electrical potential, for example the electric potential forming the mass of an electronic module with which the control member must cooperate. A second upper portion 6 is made of an electrically insulating material and is interposed between the base plate 5 and the various electrical contact blades 21 to 24 mentioned above. As such, the support plate 4 can be considered as a support part electrically insulated from the electrical contact blades 21 to 24. This support part 4 can obviously take various forms.

The use of the above-mentioned electrical contacts for interpreting the directions of rotation and the axial positions of a rod is already well known from a functional point of view. The configuration of the electrical contact blades 21 to 24, however, is specific and as such has already been the subject of two European patent applications in the name of the present Applicant respectively titled "Control device with multiple axial positions for electronic device" (request European Patent No. 02080681.6 filed 31 December 2002) and "Rotary control device for electronic apparatus" (European Patent Application No. 03011618.0 filed on May 22, 2003). We will recall here only the elements and characteristics related to the object of the present invention.

The figure 1b makes it possible to better highlight the particular shape and configuration of the electric contact blades 21 to 24. figure 1b , the cover 7 and the spring 9 have not been shown to discover the four electrical contact blades 21 to 24. The free ends 9a, 9b of the spring are however shown in section to illustrate their arrangement relative to the annular grooves of the stem 1.

From the foregoing, it will be understood that the four electrical contact blades 21 to 24 are interposed between the support plate 4, on the one hand, and the cover 7, on the other hand. In this case, each of the electrical contact blades comprises a base part (designated by the reference numeral of the concerned blade followed by the index a) sandwiched between the support plate 4 and the cover 7.

Each of the electric contact blades 21 to 24 further comprises a first flexible extension (designated by the numerical reference of the concerned blade followed by the index b) connected to the base of the blade and which is able to move freely to the Inside the cover 7 under the action of the rod 1. This first flexible extension of each electrical contact blade forms strictly speaking the movable part of each of the four electrical contacts.

As can be seen on the figures 1 a and 1b, each of the electric contact blades 21 to 24 further comprises an additional extension (designated by the numerical reference of the concerned blade followed by the index c) which is accessible from the outside of the cover 7. Each of these additional extensions 21c to 24c form, strictly speaking, the output terminal of each of the four electrical contacts, c that is to say a terminal on which is delivered an electrical signal representative of the state (closed / open) of the corresponding electrical contact. These additional extensions 21c to 24c may advantageously have a terminal "U" shape (apparent in particular in the figures 2 and 3b ) in order to be inserted into corresponding metallized holes in a printed circuit board (not shown) to which the control member is to be electrically connected.

In addition to the bases 21a to 24a, the flexible extensions 21b to 24b and the output terminals 21c to 24c, the electric contact blades 21 to 24 still have, in this example, terminations 21d, 22d, 23d, 24d, respectively, opening at the periphery of the cover 7. These terminations 21d to 24d have no real utility from the point of view of the electrical operation of the four contacts. As will be seen below, these terminations are the result of the implementation of the method of manufacturing and mounting the electrical contacts according to the invention.

Before discussing in detail the description of this manufacturing and assembly process, we will briefly explain the mode of actuation of the four electrical contacts by the rod 1.

In the particular embodiment shown in the figures, the flexible extensions 21b to 24b of the electrical contact blades 21 to 24 are each arranged to be brought into contact with the base plate 5 under the action of the rod 1 so that to establish an electrical connection with this base plate 5. As mentioned above, in operation, the base plate is brought to a specific electrical potential, for example an electric potential forming a mass. When one of the flexible extensions 21b to 24b is brought into contact with the base plate 5, the electric potential of this base plate 5 is then brought to the corresponding contact blade and this state can be detected on the terminal of output 21d, 22d, 23d, 24d of the corresponding electrical contact.

In the exemplary embodiment illustrated, the at least one end of the rod 1 which cooperates with the four electric contact blades 21 to 24 is electrically isolated, here by an insulating sheath 30, the body of the rod 1 being thus not in direct electrical contact of the blades 21 to 24. This insulating sheath 30 comprises a first portion 31 with a non-constant radius forming a cam (for example a portion of rectangular or elliptical section) for the actuation of the first set of electrical contact blades 21 , 22 and a second portion 32 essentially comprising two cylindrical portions 32a, 32b of different diameters for actuating the second set of electric contact blades 23, 24.

The first 21 and second 22 electrical contact blades of the first set are placed on either side of the rod 1, the flexible extensions 21b, 22b of these contact blades 21, 22 being oriented substantially perpendicular to the axis of the rod 1 and axially offset relative to the rod 1 so as to translate the rotations of the rod 1 in the form of electrical signals. The extensions 21b, 22b are oriented in opposite directions. The extensions 21b, 22b are also bent at a point designated by the reference numeral 210, resp. 220, (see in particular figures 2 and 3b ) so as to be directed out of the plane where the blades are supported, towards the axis of the rod 1 (the rod 1 resting at a distance above the electric contact blades). In this zone, the support plate 4 is devoid of insulation, an opening 61 being formed at this point in the insulating layer 6 to expose a portion of the base plate 5. It will also be noted that two through orifices 41, 42 are formed. in the support plate 4 (through the base plate 5 and the insulating layer 6) where are formed the ends 21c, 21d and 22c, 22d of the blades 21, 22.

Under the action of the rod 1, in this case during a rotation of the rod 1 about its axis, the cam portion 31 of the sheath 30 successively actuates the two flexible extensions 21b, 22b of the contact blades 21, 22, causing a slight downward movement of the points 210, 220 where the flexible extensions 21b, 22b are bent. These points 210, 220 are then brought into contact with the base plate 5 through the opening 61 formed in the insulating layer 6. Preferably, two bosses 51, 52 are arranged opposite the points 210, 220 where the extensions 21 b, 22b are bent (these bosses 51, 52 are indicated in broken lines in the Figure 1 (b) .

The first 23 and second 24 electrical contact blades of the second set are also placed on either side of the rod 1, this time in the vicinity of the end of the rod 1 and the portion 32 of the sheath 30. In this example, the flexible extensions 23b, 24b of these blades 23, 24 (at least the end portions of these extensions which cooperate with the rod 1) are oriented substantially parallel to the axis of the rod 1 and again shifted axially with respect to this rod 1 so as to translate the axial positions of the rod 1 in the form of electrical signals. A portion of each flexible extension 23b, 24b is arranged to cooperate with the end 32 of the sheath 30 placed on the rod, while another adjacent portion of each flexible extension 23b, 24b is arranged to cooperate with a contact pad 53, resp. 54, coming from material with the plate of base 5. At this point, the support plate 4 is again provided with a through hole 43 in which the extensions 23c, 23d, 24c and 24d open out of the blades 23, 24. The contact pads 53, 54 are here made under the form of extensions of the base plate 5 folded through the orifice 43 in the direction of the rod 1. These contact pads 53, 54 are also visible in the figures 3d to 3f .

It should be noted that the flexible extensions 23b, 24b are configured and prestressed to come into contact laterally with the contact pads 53, 54 as illustrated in FIG. figure 1b . This contact is maintained as the rod 1 is not brought into a position where its end exerts an action to move the corresponding blade. In the illustrated position (extreme end position), the two blades 23, 24 are in contact with the contact pads 53, 54. In the intermediate stable axial position (intermediate pulled position), the blade 23 is spaced from the contact pad 53 In the last stable axial position (neutral position), the two blades 23, 24 are spaced apart from the contact pads 53, 54. Finally, in the unstable pushed position (position accessible from the aforementioned neutral position), the blade 23 temporarily returns to contact of the stud 53 to be again spaced after return to the neutral position, this return being provided by the return force of the spring 9.

We will not dwell more on the description of the operation of the electrical contacts, this operation not being directly related to the object of the claimed invention.

With reference to figures 2 and 3a to 3f , we will now describe an embodiment of the present invention for the manufacture and assembly of the electrical contacts of the above-mentioned multifunctional crown rod.

In general, the proposed method proceeds as follows. This process first starts with the stamping and preforming of a plate of an electrically conductive material to form an intermediate base plate comprising a support structure and a plurality of electrical contact blades still mechanically linked to the structure. support by a plurality of attachment points (cf. figure 2 ), each electrical contact blade comprising a base and a flexible extension connected to the base to form the movable portion of an electrical contact operable by the control member. Then follow a positioning step (cf. figures 3a and 3b ) of the intermediate base plate on a first electrically insulated support part of the contact blades, a fixing step (cf. Figures 3c , 3d and 3rd on the first support part of a second electrically isolated support part of the contact blades so that each of the electrical contact blades is held between the first and second support parts by its base, and finally a breaking step ( cf. figure 3f ) of the plurality of attachment points connecting the plurality of electrical contact blades to the support structure such that all electrical contact blades are made independent and electrically isolated from each other.

The first stamping and preforming step is preferably performed to produce a strip comprising a plurality of identical sets of electric contact blades. This is for example the case in the implementation example which will now be described. The figure 2 shows in fact a strip 200 of electrically conductive material (for example a metal of the steel or copper type) comprising several identical sets of blades 21 to 24 for producing the electrical contacts of the aforementioned multifunctional crown rod (several similar games are thus made on the strip 200, only two being illustrated in the figure 2 ). This band 200 is obtained according to conventional stamping methods. Several orifices 250 are provided on the strip 200 to allow its handling and / or positioning. In the configuration illustrated in figure 2 it may therefore be noted that each of the electric contact blades 21 to 24 is mechanically bonded to a support structure 25 to form the strip 200, the extensions 21d to 24d above forming points of attachment between the strips 21 to 24 and the support structure 25.

The figure 3a shows a perspective view of the hood 7 already mentioned, this figure 3a showing in this view, the opening 7c through which the rod 1 is housed once mounted, and several mounting posts 75, 76, 77. The four tenons 75 are intended to allow the fixing of the cover 7 on the support plate 4 through mounting holes 45 as will be seen hereinafter, while the pins 76, 77 are intended to ensure proper positioning of the cover 7 on the support plate 4. In this example, the cover 7 also advantageously comprises a set of indentations 71 to 74 corresponding to the general shape of the bases 21a to 24a of the four electrical contact blades 21 to 24. These indentations promote a good resistance of the various blades to mounted state. It will be noted that openings (not referenced) are also provided to allow the passage of the flexible extensions 21b to 24b of the electrical contact blades 21 to 24 inside the cover 7. It should be noted that the impressions could be made in one or the other of the support pieces.

The figure 3b shows a next step of the method where the strip 25 comprising the blades 21 to 24 is positioned on the cover 7. It can thus see the bases 21b to 24b of the blades embedded in the recesses 71 to 74 corresponding.

After positioning the blades 21 to 24 on the cover 7, the insulating layer 6 and the base plate 5 are then positioned on the strip to form the plate support 4 ( Figures 3c and 3d ). After mounting the base plate 5, it will be noted that the tenons 75, 76, 77 of the cover 7 are housed in the mounting holes 45, 46, 47 corresponding and that the openings 41, 42, 43 formed in the support plate 4 allow access to the attachment points 21 d to 24d of the electrical contact blades 21 to 24.

As illustrated in figure 3e , the ends 75 of the tenons are then plastically deformed to make the cover 7 and the support plate 4 integral and maintain the various contact blades 21 to 24. It will be understood that the cover 7 could be made integral with the support plate 4 by means of other means (eg welding, gluing, clipping, screwing, etc.).

As illustrated in figure 3f the electrical contact blades 21 to 24 can then be separated from the support structure 25 to be made independent and electrically insulated from each other. In the example, this is advantageously achieved by using a tool (not shown) to break the various points of attachment 21 d to 24d of the blades through the orifices 41, 42 and 43 provided to facilitate this operation. In order to ensure a facilitated breaking of the points of attachment, the section of the contact blades can be reduced locally to promote the cutting of the blade along a predetermined line.

The various electrical contacts of the control member are thus made. It remains only to mount the control member itself (in this case, the rod 1 provided with its ring 10 and the spring 9 of axial positioning of the rod 1) and to make the electrical connections between the output terminals of the electrical contacts and the appropriate electronic module. In the case in point, note that the rod 1 and the ring 10 are typically mounted at an ultimate stage of manufacture, in this case after mounting the movement of the timepiece and insertion into its box .

It will be understood in general that various modifications and / or improvements obvious to those skilled in the art can be made to the embodiments described in the present description without departing from the scope of the invention defined by the appended claims. As already mentioned in the preamble, the invention is not limited to the production of electrical contacts for multifunctional rod-rings but can be applied by analogy to the realization of any electrical contact for a small-sized control member, for example for pushbuttons or control devices of the type similar to joysticks. It will further be understood that the method could be exploited to simultaneously manufacture and assemble the electrical contact (s) of a plurality of control members.

Claims (10)

1. Method for manufacturing and mounting electric contacts for control members of small dimensions, particularly for control members used in the horological field, including the following steps:

   a) stamping and pre-shaping a plate of electrically conductive material for forming an intermediate base plate (200) including a support structure (25) and a plurality of electric contact strips (21 to 24) still mechanically connected to said support structure (25) by a plurality of points of attachment (21 d to 24d), each electric contact strip including a base (21 a to 24a) and a flexible extension (21 b to 24b) connected to said base to form a mobile part of an electric contact that can be actuated by a control member (1, 10);

   b) positioning the intermediate base plate (200) on a first support piece (7) electrically insulated from said electric contact strips (21 to 24);

   c) fixing onto said first support piece (7) a second support piece (4) electrically insulated from said electric contact strips (21 to 24) such that each of said electric contact strips (21 to 24) is held between said first (7) and second (4) support pieces via its base (21 a to 24a), and

   d) breaking said plurality of points of attachment (21 d to 24d) connecting the plurality of electric contact strips (21 to 24) to said support structure (25) such that all of the electric contact strips (21 to 24) are made independent and electrically insulated from each other.
2. Method according to claim 1, characterised in that said first or second support piece (7, 4) includes orifices (41, 42, 43) arranged for facilitating breakage of said plurality of points of attachment (21d to 24d).
3. Method according to claim 1 or 2, characterised in that said step of fixing the second support piece (4) onto the first support piece (7) includes, in particular, welding, bonding, snap-fitting, screwing or riveting said first and second support pieces.
4. Method according to any of preceding claims, characterised in that said second support piece (4) including a base (5) made of an electrically conductive material covered with an insulating material (6), said base (5) being intended to be brought to a determined electric potential to act as a contact zone common to all of said electric contact strips (21 to 24) and with which each of the flexible extensions (21 b to 24b) of said electric contact strips can be brought into contact to establish an electric connection, each of said electric contact strips (21 to 24) further comprising an additional extension (21 c to 24c) forming an output terminal for each of said electric contact strips.
5. Method according to any of the preceding claims, characterised in that said first or second support piece (7, 4) includes a plurality of stamps (71 to 74) into which said bases (21 a to 24a) of the electric contact strips (21 to 24) are embedded during the fixing step.
6. Method according to any of the preceding claims, characterised in that the section of said electric contact strips (21 to 24) is reduced locally in proximity to the points of attachment (21 d to 24d) to facilitate the cutting of the electric contact strips (21 to 24) during the breaking step.
7. Method according to any of the preceding claims, characterised in that said stamping and pre-shaping step includes the preparation of a tape (200) including a plurality of identical sets of electric contact strips (21 to 24).
8. Method according to any of the preceding claims, for making a multifunction stem-crown (1, 10) for a timepiece, characterised in that said stamping and pre-shaping step includes the preparation of a first set of electric contact strips (21, 22) for detecting rotations of said stem-crown and a second set of electric contact strips (23, 24) for detecting axial positions of said stem-crown.
9. Method according to claim 8, characterised in that said stem-crown (1, 10) includes an electrically insulated end (30) for actuating said electric contact strips (21 to 24), said end (30) including a first part (31) of non-constant radius forming a cam for actuating said first set of electric contact strips (21, 22) and a second part (32) including several cylindrical portions (32a, 32b) of different diameters for actuating said second set of electric contact strips (23, 24).
10. Method according to claim 9, characterised in that said first set of electric contact strips includes first (21) and second (22) electric contact strips placed on either side of the stem-crown (1, 10), the flexible extensions (21 b, 22b) of said first and second electric contact strips (21, 22) being oriented substantially perpendicularly to the axis of the stem-crown and axially shifted with respect to the stem-crown so as to be able to convert the rotations of said stem-crown into electric signals,
    and in that said second set of electric contact strips includes third (23) and fourth (24) electric contact strips placed on either side of the stem-crown (1, 10), the flexible extensions (23b, 24b) of said third and fourth electric contact strips (23, 24) being oriented substantially parallel to the axis of the stem-crown and axially shifted with respect to the stem-crown so as to be able to convert the axial positions of said stem-crown into electric signals.

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