MEASURING HANGER FOR CLOCK MOVEMENT

Description

Technical field of the invention

[0001] The invention relates to a measuring support for a watch movement, arranged to constitute a lower support for a cap comprising a watch movement or a watch head comprising a watch movement, in a position of support under constraint of said cap or said watch head on said measuring support.

[0002] The invention relates to the field of watch movement control, in particular the control of rate and / or amplitude of mechanical movements. Technological background

[0003] To control and measure the rate and / or amplitude of a watch movement, it is known to perform an acoustic control, to capture the sound emitted by the escapement of a caliber (mounted in a cap or fitted into a watch head) in order to measure the rate and amplitude of the movement.

[0004] There are many ways to measure the sounds (vibrations) emitted by a movement or a watch. For example, a contact microphone, an airborne microphone, or an optical system such as a laser vibrometer are all possibilities.

[0005] The overhead microphone is too sensitive to ambient noise and even internal noise from the measuring device. Often in watchmaking, movements are tested in batches of ten units: if ten movements are running simultaneously, each microphone should only pick up the movement it is dedicated to, and not the immediately adjacent movements.

[0006] The laser vibrometer is used in laboratories, but is far too expensive, complex, and bulky for mass production applications. It is also highly sensitive to vibrations and environmental variations.

[0007] An optical solution using light emission, for example with an LED, and analysis of the reflected signal, is better suited for integrating motion into complete batch processing boxes, but the return signal is very weak, practically imperceptible, and again difficult to isolate from ambient noise. Furthermore, this solution is too power-intensive for a portable system such as a box containing the motion sensors and associated components.

[0008] Therefore, a sensor consisting of a piezoelectric element used as a contact microphone is generally used to perform such measurements. Piezoelectric elements are available in various types and geometries. Typically, they come in the form of a bar or a disc, and in single or bimorphic types (two piezoelectric elements stacked one on top of the other). Bimorphic bars are generally much more sensitive but more complex to contact and, above all, much more expensive.

[0009] But, even with a piezo sensor, while such control does not pose difficulties on a static bench, it is more delicate to perform on a moving object, for example on a crown or on a watch head mounted in a case and manipulated by a robot or similar, or on a manufacturing or control line.

[0010] Indeed, the piezoelectric element is fragile. Directly pressing the object whose sound you wish to capture against it could damage it. It is important to avoid subjecting it to mechanical stress as much as possible.

[0011] Therefore, a mechanical element is needed to serve as an interface between the piezo and the movement, and also to hold the piezo in position within the measuring device.

[0012] It is also necessary to ensure that only the sound from the clockwork movement is measured by the piezo, and therefore this sensor must be isolated as much as possible from external disturbances, in particular acoustic disturbances from other movements being tested nearby.

[0013] Document CH 169 093 A describes a chrono comparator where the pulses of each timepiece are measured by two isolated microphones: to avoid any acoustic coupling between the microphones, each is enclosed in a soundproof box and the timepiece being tested is mounted on a plate mounted on insulating supports. Summary of the invention

[0014] The invention aims to provide an economical solution to the problem of the holding of a piezo sensor for a control of step and / or amplitude, in particular embedded in a box or any other mobile support in space, and a solution allowing to achieve a less sensitivity to ambient noise than current systems.

[0015] For this purpose, the invention relates to a measuring support according to claim 1. Brief description of the figures

[0016] The aims, advantages and features of the invention will be better understood upon reading the detailed description that follows, with reference to the attached drawings, where: there figure 1 represents, schematically, partially and in cross-section, a cap equipped with a clockwork mechanism, in a control position which is a support position under constraint of this cap on a measuring support according to the invention; figure 2 represents in a similar way to the figure 1, a watch head containing a watch movement, in a control position which is a constrained support position of this watch head on the same measuring support as that of the figure 1 ; there figure 3The diagram schematically represents, in cross-section along an axis of revolution, a particular and non-limiting variant of a measuring support according to the invention, comprising a bell-shaped inverted bell, the flared end of which faces the object to be measured, here a dome enclosing a movement. The end of the control rod is in contact, along a substantially frustoconical bearing area, with the inner part of this bell, which in this particular and non-limiting embodiment is substantially conical. This bell guides the vibrations towards a more massive concentrating part, attached to a base beneath which a sensor is fixed, here a piezo sensor in this particular example. This base has a slot to receive the cable connecting the sensor to an electronic module; the figure 4represents schematically, in cross-section by an axis of revolution, the same measuring support as on the figure 3 , which is here supported by a measurement area of ​​a watch head, more specifically between two lugs adjacent to this watch head, according to a roughly annular support area; the figure 5 represents, schematically and in cross-section, another measuring support which is not of revolution symmetry, but of plane symmetry with respect to the cutting plane, and which has a rounded upper end for a more point contact. Detailed description of the invention

[0017] To provide an effective solution for the protection of the sensor, the invention proposes to fix the sensor on a measuring support, which supports the mechanical force when pressing on the element to be controlled.

[0018] A simple piezoelectric disc, mass-produced and well-known in the watchmaking industry (used as a buzzer), gives perfectly satisfactory results and is therefore suitable for industrial applications. In particular, the invention addresses the industrial setup in which movements housed in cases or mounted in watch heads are stored in batches in transport boxes on production or inspection lines. Such boxes circulate on fairly long cycles, lasting several days or weeks, depending on the nature and frequency of the operations to be performed, especially for chronometric testing. It is therefore necessary to have inexpensive measuring devices, since they remain stationary on these boxes, and that can withstand handling on conveyors, in stacker cranes, or other handling equipment.

[0019] Since sound is captured by contact, different options exist. The point of contact between the sensor and the object to be measured can vary.

[0020] Ideally, the contact with the sound source should be as direct and rigid as possible. In the case of a watch movement, the mainspring is a suitable element, and the only viable one for movements mounted in a crown. For movements housed in a watch head, contact can also be achieved via the case, the case back, or the case middle, for example. Contact with the crystal is not always ideal, due to the gaskets that dampen the vibration.

[0021] In the case of watch crowns or heads grouped in multiple batches of 10 in a processing box, sensors must be provided that can measure this or these dozens of movements (in crowns or cased), at a rate of one sensor per movement, inserted in a box of given dimensions.

[0022] One challenge is ensuring compatibility with the wide variety of watch types, which have varying geometries. The case dimensions necessitate aligning the watches. Access to the escapement stem is not guaranteed, nor is it always in the same position. For cased movements, checking the movement between the lugs yields good results; moreover, this area allows for minor marks or localized wear without compromising the watch case's aesthetics. Therefore, it is advantageous to position the sensor so that it makes contact with the case at the lugs for watches, and with the escapement stem for crown-mounted movements.

[0023] In order for the watch head and the crown to be positioned in the same compartments of a transport case, this requires contact areas with the sensor in two different positions.

[0024] The invention also relates to a measuring support 500 for a watch movement, which is arranged to provide a lower support for a cap 200 carrying a watch movement 400 or a watch head 300 carrying a watch movement 400, in a constrained bearing position of the cap 200 or the watch head 300 on the measuring support 500. For example, this cap 200 or this watch head 300 is pushed towards the measuring support 500 and held in contact with the measuring support 500 by compression means pushing this cap 200 or this watch head 300 on the side opposite to the side of contact with the measuring support 500, in particular by at least one resilient element 80 which is constrained to bear on this cap 200 or this watch head 300 on the side opposite to the side of contact with the measuring support. 500.

[0025] In a preferred embodiment of the invention, this measuring support 500 comprises a bell 501 in the shape of an inverted bell, with a conical or evolving internal profile, the most flared side of which is turned towards the cap 200 or the watch head 300 to be tested. This bell 501 guides the vibrations towards a more massive concentrator portion 502, which is integral with a base 503 under or on which is held a measuring sensor 510 arranged to listen to the rate and / or amplitude of a watch movement 400 enclosed in a cap 200 or a watch head 300, in the position where this cap 200 or this watch head 300 rests under stress on the measuring support 500.

[0026] More specifically, this 510 measurement sensor is a piezo sensor.

[0027] To ensure good transmission of the sound from the movement 400 to the piezo sensor 510, the number of interfaces must be minimized, and the best possible contact must be achieved at each interface. The piezo-bell connection must therefore be rigid, which is easily accomplished by gluing the piezo element over its entire surface to or onto the measuring support 500, particularly with a rigid adhesive such as cyanoacrylate. More specifically, this measuring sensor 510 is glued over its entire contact surface with the base 503 using cyanoacrylate adhesive.

[0028] More specifically, the base 503 has a slot 504 to receive a connecting cable 520 for linking the measuring sensor 510 with an electronic module 51.

[0029] More specifically, the inner part of pavilion 501 is substantially conical.

[0030] More specifically, as seen on the figure 3, the pavilion 501 has, at its most open side, an outer diameter DE, smaller than the lug spacing DEC of the watch cases 300 to be measured, and an inner diameter DI greater than the diameter of the crowns of the movements 400 enclosed in the caps 200 to be measured, these crowns coming into contact with the inner support surface 511 of the pavilion 501. This geometry responds well to the space constraints, and makes the measuring support 500 very versatile.

[0031] Specifically, the 500 measurement support is made of a hard material or is metallic. Indeed, a bell made of a hard material ensures good transmission. Tests show particularly good results with a bell made of aluminum alloy.

[0032] More specifically, the 500 measuring support is made of aluminum alloy.

[0033] More specifically, the 500 measuring support is made of bronze or cupro-aluminum.

[0034] Mounting the 510 piezo sensor on a rigid component like the bell of the 500 measuring support raises the resonant frequency of the entire sensor system (piezo + bell) compared to that of the piezo alone. This significantly shifts the resonant frequency outside the measured frequency range, preventing erratic behavior. Specifically, the 500 measuring support is weighted with an inertial mass.

[0035] More specifically, and as can be seen on the figures 3 and 4 , the 501 horn has rotational symmetry with respect to an AC horn axis.

[0036] More specifically, as seen on the figure 5 The 501 pavilion is not rotationally symmetrical, but could be planarly symmetrical, or otherwise, on this figure 5the end 505 of the pavilion 501 turned towards the cap 200 or the watch head 300 to be measured has at least one contact surface which is locally substantially spherical or cylindrical.

[0037] In particular, the base 503 is surrounded by a base made of flexible and resilient material, preferably removable, notably by clipping, and which has its only means of attachment to an external structure: the base 503, and therefore the measuring support 500, can be suspended while remaining in support under stress with the cap 200 or the watch head 300.

[0038] There figure 3 shows the contact between the distal end 411 of the control member 410 in the case of a cap 200, resting on an internal bearing surface 511 of the pavilion 501 of the measuring support 500.

[0039] There figure 4shows the contact between a support area 301, here for example between the lugs of a watch head 300, and the end of the pavilion 501 of the measuring support 500.

[0040] At the base 503, a groove 504 allows the passage of a 520 cable or similar connected to an electronic module or similar. The base 503 is preferably the fixing element to an external structure, notably through a groove in a base made of flexible and resilient material, and secured by a bead that ensures its retention.

[0041] The geometry of the bell forming the 501 horn must direct the sound towards the center of the 510 piezo pickup. A point contact at the center would probably be ideal. But realistically, the inverted cone shape is preferable. One could somewhat compare its operation to that of a drum, where it is clear that the sound is much better and more powerful when struck in the center of the membrane rather than on the edges.

[0042] Bell-shaped or inverted cone-shaped geometry solves two problems: by providing the possibility of establishing contact between the sensor 501 and watch heads 300 on the case, or movements 400 in crown 200 on the stem 410, in the same footprint; by improving the efficiency of sound capture thanks to the shape which conducts and concentrates vibrations towards the center of the sensor.

[0043] The specific measuring support implemented by the invention offers, in addition to the advantage of a high-quality measurement that is far more reliable than probing a crystal or watch case back, considerable versatility since it is suitable for both watch crowns and watch heads. In the latter case, the support between the lugs is advantageous, as it avoids contact with the watch head's surface. In short, the invention provides an economical solution to the problem of securing a sensor, particularly a piezoelectric sensor, for rate and / or amplitude monitoring, and offers better protection against ambient noise than current systems.

Claims

1. A measuring jig (500) for a horological movement, designed to provide a lower support for a calotte (200) comprising a horological movement (400) or a watch head (300) comprising a horological movement (400), in a position in which said calotte (200) or said watch head (300) is held in place against said measuring jig (500), characterised in that said measuring jig (500) comprises a pavilion (501) in the shape of a reverse bell, the flared side of which is facing said calotte (200) or said watch head (300) to be controlled, this pavilion (501) being designed to guide vibrations towards a more massive part acting as a concentrator (502), attached to a base (503) under which is held a measurement sensor (510) designed to listen to the rate and / or amplitude of a said horological movement (400) enclosed in said calotte (200) or said watch head (300), in the position in which said measuring jig (500) is held against said calotte (200) or said watch head (300), characterised in that said concentrator (502) has a generally truncated conical shape, the smaller part of which is attached to said base (503).

2. The measuring jig (500) according to claim 1, characterised in that said measurement sensor (510) is a piezo sensor.

3. The measuring jig (500) according to claim 1 or 2, characterised in that said measurement sensor (510) is glued over its entire contact surface to said base (503) with a cyanoacrylate glue.

4. The measuring jig (500) according to any of claims 1 to 3, characterised in that said base (503) comprises a slot (504) for holding a connecting cable (520) for connecting said measurement sensor (510) to an electronic module (51).

5. The measuring jig (500) according to any of claims 1 to 4, characterised in that the inner part of said pavilion (501) is substantially conical.

6. The measuring jig (500) according to any of claims 1 to 5, characterised in that said pavilion (501) has, at its most open side, an outer diameter (DE) that is less than the lug width of the watchcases (300) to be measured, and an inner diameter (DI) that is greater than the diameter of the crowns of the movements (400) enclosed in the calottes (200) to be measured, said crowns contacting an inner support surface (511) of said pavilion (501).

7. The measuring jig (500) according to any of claims 1 to 6, characterised in that said measuring jig (500) is made of hard material or is metallic.

8. The measuring jig (500) according to claim 7, characterised in that said measuring jig (500) is made of aluminium alloy.

9. The measuring jig (500) according to claim 7, characterised in that said measuring jig (500) is made of bronze or of cupro-aluminium.

10. The measuring jig (500) according to any of claims 1 to 9, characterised in that said measuring jig (500) is weighted with an inertial mass.

11. The measuring jig (500) according to any of claims 1 to 10, characterised in that said pavilion (501) is rotationally symmetric about a pavilion axis (AC).

12. The measuring jig (500) according to any of claims 1 to 10, characterised in that the end (505) of said pavilion (501) facing said calotte (200) or said watch head (300) to be measured comprises at least one contact surface that is locally substantially spherical or cylindrical.

13. The measuring jig (500) according to any of claims 1 to 12, characterised in that said base (503) is surrounded by a sole made of flexible, resilient material comprising its only means of attachment to an external structure.