HK1103455B - Control stem device for a watch - Google Patents

Description

Control stem device for a watch

Technical Field

The present invention relates to a control stem device for a watch, such as a winding and time-setting stem, comprising a first stem rotating about its longitudinal axis and provided with means for fixing the first stem to a manual control crown external to the watch, and a second rotating stem substantially parallel to and offset with respect to the first stem, and provided with means for selectively driving in rotation a winding mechanism and a time-setting mechanism, said first and second stems being connected in rotary motion by a transmission mechanism.

Background

For mechanical watches with multiple functions (combination), when these function elements have to occupy the space between the dial and the basic movement and thus cause the movement to be situated below the median plane of the watch, it is advantageous to use two stems offset in height and kinematically connected instead of the usual winding stem in the form of a single part or two aligned parts. The external crown of the traditional winding stem is much closer to the back cover of the watch case than to the bezel, which is inconvenient and aesthetically unpleasing. The double stem arrangement allows the crown to be held in a conventional and convenient position, i.e. in the middle of the case.

In known devices of this type, such as those disclosed in CH patent No.691632 and EP patent application No.1134628, the two stems are connected in rotary motion by a transmission mechanism and are also fixed in translation relative to each other, so that the second stem follows the first stem (moves) when the user pulls out the control crown. The second stem, i.e. the one extending into the movement, therefore fulfils all the functions of the traditional stem and must be fitted with the same components (pull-out, sliding pinion, winding pinion, etc.) as the traditional stem. The designer is forced to slightly displace these parts towards the inside of the movement, due to the position occupied by the gear train connecting the two stems. Furthermore, the connection for fixing the two stems in translation requires a movable frame housing the gear train, which increases the space requirement of the device. Given that the axial position of the first stem is mainly displayed on the second stem, the axial play that inevitably exists in the frame makes this axial position imprecise.

Disclosure of Invention

The object of the present invention is to propose an improved (control stem) device with respect to the prior art, which is simpler and more compact.

There is therefore provided a device of the type stated in the preamble, characterized in that said first stem is mounted so as to be axially movable at least between an operating position associated with said first function and an operating position associated with said second function, so as to actuate, by sliding between said positions, a pull-out mechanism cooperating with a sliding pinion fixedly mounted in rotation on said second stem and axially movable, to pass said sliding pinion from one axial position to the other, said sliding pinion being in mesh, in one of said positions, with the mechanism for the first function and in the other with the mechanism for the second function.

The second stem is thus made switchable between the two functions by axial movement of the first stem using a conventional pull-out mechanism, which avoids the above-mentioned drawbacks of a translationally movable frame. The pull-out mechanism has the advantage of being reliable and durable and of low height, and defines itself, by means of the spring it contains, the position associated with both functions. Furthermore, the device can easily allow the watch manufacturer to disengage the pull-out piece from the first stem, which makes it possible for the first stem to be mounted and dismounted through a corresponding opening in the watch case, as in the case of a traditional segmented stem (brooken stem).

According to a preferred embodiment of the invention, the second shank comprises a section with a non-circular, for example square, cross-section, on which the sliding pinion is slidably engaged, said pinion having a circumferential groove in which one end of the rod of the pull-out mechanism engages. This provides a very compact construction with a simplified support.

Drawings

Further characteristics and advantages of the invention will emerge from the following description, which shows a preferred embodiment by way of non-limiting example with reference to the accompanying drawings, in which:

figure 1 is a longitudinal section of the (control stem) device according to the invention in the winding position;

figure 2 shows the device of figure 1 in a time-setting position; and

figure 3 is a plan view of a pull-out mechanism forming part of the device of figure 1.

Detailed Description

The device shown in the figures comprises two winding and time-setting stems, namely a first stem 1 and a second stem 2, whose respective axes of rotation 3 and 4 are parallel, but offset in height with respect to each other in a perpendicular or oblique direction with respect to the general plane of the watch movement. These stems are connected by two kinematic connections, namely a transmission 5, which is constantly engaged and transmits the rotary motion from one stem to the other, and a pull-out 6, shown in fig. 3, which pull-out 6 transmits the axial motion from the first stem 1 to a sliding pinion 8, which sliding pinion 8 is slidably mounted on a square section 9 of the second stem 2 and, thanks to the central square hole, this sliding pinion 8 is fixed non-rotatably on the second stem 2. In the embodiment illustrated herein, the stem 2 does not slide, i.e. the axial position of the stem 2 is fixed.

The entire device is supported from the bottom plate of the watch movement by fixing elements or bridges 10, 11, 12, 13, 14 and 15. Mounted on these fixed elements are also a winding mechanism 20 and a time-setting mechanism 24, of which the winding pinion 21 and the intermediate wheel 22 of the winding mechanism 20, as well as an intermediate setting wheel (motion work wheel)25 of the time-setting mechanism 24, which rotates on a column 26, can be seen in the drawing.

The first stem 1 comprises a first cylindrical portion 30 and a second cylindrical portion 31 of smaller diameter than said first portion, said first and second cylindrical portions being slidably mounted in the holes of the fixing elements 14 and 13 acting as supports, so that the stem 1 can slide between a winding position shown in fig. 1 and a time-setting position shown in fig. 2. In other embodiments, stem 1 may have a third position, for example for setting a date. As with a traditional winding stem, the stem 1 comprises a threaded end 32 passing through the watch case and carrying a manual control crown located outside the watch case.

One portion 34 of stem 1, with a square cross section, engages in a hole of matching cross section of a first-stage pinion 35, first-stage pinion 35 being axially retained between fixing elements 13 and 14. The central hole of pinion 35 also comprises a section which is circular in cross-section and is mounted on cylindrical portion 36 of element 13, cylindrical portion 36 of element 13 acting as a support for radially supporting pinion 35 when stem 1 is removed, for example to mount a movement. In the cylindrical portion 30 of the stem 1 there is provided an annular groove 37 in which a post 39 of a pull-out piece 40 engages. When the handle manufacturer wishes to remove the stem 1, the pull-out piece can be lowered to release the post from the recess.

Both ends of the stem 2 are provided with cylindrical pivots. The jewel 42 mounted in the element 15 and the hole 43 of the element 11 form a rotary support for supporting the stem 2 and axially retaining the stem 2. Pinion 44 fixed to stem 2 meshes constantly with pinion 35, forming the last pinion of the transmission. According to the principle forming the subject of the aforementioned EP patent application No.1134628, this transmission mechanism may, if desired, comprise an intermediate pinion between the pinions 35 and 44, so that the two stems 1 and 2 rotate in the same direction, but the device according to the invention does not normally require this additional pinion. Furthermore, it should be noted that the device described herein does not require any support on the watch case.

The pinion 44 is flanked by a winding pinion 21, which winding pinion 21 can axially abut against the pinion 44 and is freely mounted on a cylindrical shoulder 46 of the stem 2. The pinion 21 is of conventional construction and comprises a toothed transversal toothing 47 of the belite (Breguet) type, which transversal toothing 47 is able to cooperate with a matching toothed transversal toothing 48 of the sliding pinion 8, a toothed toothing 50 meshing on the intermediate setting wheel 25 in the time-setting position shown in figure 2. The sliding pinion 8 also has a peripheral groove 51 in which a lever 52 of the pull-out mechanism 6 engages.

Fig. 3 shows that the pull-out mechanism 6 comprises, in addition to the pull-out part 40 and the lever 52, a fixed pull-out bridge 54, which comprises a jumper spring 55, which jumper spring 55 is provided with two notches 56 that cooperate with pins 57 of the pull-out part. The pivot axis of the pull-out piece 40 is located at 58 and the pivot axis of the lever 52 is located at 59, said lever being pushed back towards the right in the drawing by the spring 60.

The device operates in the following manner. In the winding position shown in fig. 1, first stem 1 is in the pushed-in position, so that the crown carried by first stem 1 rests against the watch case. The pull-out element 40 is held in the position shown in fig. 3 by a positioning rod spring 55, so that it holds the first stem 1 by its post 39. The rod 52, pushed by the spring 60, keeps the sliding pinion 8 engaged on the winding pinion 21. Thus, when the user rotates first stem 1, it drives in rotation first-stage pinion 35, second pinion 44, second stem 2, sliding pinion 8, winding pinion 21 and winding mechanism 20.

When the user places first stem 1 in the pulled-out position shown in fig. 2, pull-out piece 40, driven by means of post 39, pivots so that rounded end 62 of the pull-out piece pushes against lever 52, causing sliding of sliding pinion 8, releasing sliding pinion 8 from winding pinion 21 so that sliding pinion 8 engages on intermediate setting wheel 25. Therefore, when the user rotates the crown fixed to the first stem, the time-setting mechanism 24 is rotated in the same direction. The operation performed on first stem 1 is therefore exactly the same as the operation performed on the single winding stem.

According to a variant not shown, second stem 2 is able to slide and is fixed on sliding pinion 8. The pinion gear 44 must be long in order to remain engaged with the pinion gear 35 during sliding. Furthermore, winding pinion 21 must be held axially so that it does not slide with stem 2, i.e. the length of the structure will be slightly greater than that shown in fig. 1 and 2.

It should also be noted that in the illustrated embodiment, the control stem device is applied to the winding and time-setting functions. Of course, the device according to the invention can also be used for any other function, such as date, time zone or alarm time setting.

Claims (10)

1. Control stem device for a watch, comprising a first stem (1) rotating around its longitudinal axis and provided with means (32) for fixing it to a manual control crown external to the watch, and a second stem (2) substantially parallel to the first, offset with respect to the first and fixed in rotary motion with respect to a sliding pinion (8), the sliding pinion (8) being movable along the longitudinal axis of the second stem for selectively driving in rotation a mechanism (20) for a first function and a mechanism (24) for a second function, the first and second stems being connected in rotary motion by means of a transmission mechanism (5), characterized in that the second stem (2) has a fixed axial position, while the first stem (1) is mounted so as to be able to rotate at least in an operating position associated with the first function and in relation to the second function Is axially movable between associated work positions, so as to actuate, by sliding between said work positions, a pull-out mechanism (6) comprising a rod (52) engaged in a peripheral groove of said sliding pinion (8) so as to cooperate with said sliding pinion (8) and transmit to it the axial movement of the first stem (1) to rotate it from one axial position to another, said sliding pinion (8) being in mesh, in one of said axial positions, with a mechanism (20) for a first function and in another of said axial positions, with a mechanism (24) for a second function.

2. Device according to claim 1, characterized in that said working position of said first stem (1) associated with said first and second functions is stable.

3. Device according to claim 1 or 2, characterized in that said second stem (2) comprises a section (9) with a non-circular cross section, said sliding pinion (8) being slidably engaged on said section (9).

4. The apparatus of claim 3, wherein the non-circular cross-section is square.

5. Device according to claim 1, characterized in that the second stem (2) is supported at both ends by a fixed element (11, 15) of the watch movement.

6. Device according to claim 3, characterized in that said transmission mechanism has a gear train and comprises a first stage pinion (35) and a last stage pinion (44), said first stage pinion (35) comprising a central hole with a non-circular cross section slidably engaged on a non-circular section of the first stem, said last stage pinion (44) being fixed on the second stem and constantly meshing with the first stage pinion.

7. Device according to claim 6, characterized in that said first-stage pinion (35) is held stationary in the axial direction by a fixed element (13, 14) supporting the first stem.

8. Device according to claim 7, characterized in that said first-stage pinion (35) is supported by at least one of said fixed elements (13) acting as a support.

9. Device according to claim 6, characterised in that the side of the last-stage pinion (44) is connected to a winding pinion (21), which winding pinion (21) is freely mounted on the second stem and is arranged for cooperating with a contrate toothing (48) of the sliding pinion (8).

10. The apparatus according to claim 1 or 2, wherein the first function is a winding function and the second function is a time setting function.