CH705231A2 - Clockwork movement, has eccentric being arranged such that eccentric adjusts center distance between escapement pinion and seconds wheel when eccentric is turned around axle of Archimedes or optimized Archimedes spiral - Google Patents

Abstract

The movement (30) has a module i.e. escapement platform (36) provided with a mobile i.e. escapement pinion (18), gearing with another mobile i.e. seconds wheel (32), that is pivoted on a plate (4), where the module is mounted on the plate. A positioning unit positions the module on the plate, where the unit is formed by an eccentric (40), and circumference (42) of the eccentric defines Archimedes/optimized Archimedes spiral on major portion. The eccentric is arranged such that the eccentric adjusts a center distance (L) between mobiles when eccentric is turned around an axle (46) of spiral. An independent claim is also included for a method for adjusting a center distance between clockwork mobiles.

Description

Technical area

The present invention relates to a watch movement comprising a module provided with a first mobile meshing with a second mobile pivoting in a base on which is mounted the module. In particular, the invention relates to a clockwork comprising an exhaust-holder forming a module in which the exhaust is arranged, namely the balance spring, the anchor and the escapement mobile. This mobile exhaust is formed of an exhaust plate and an exhaust pinion which, in the finished movement, meshes with a wheel of the train mounted on the plate on which is fixed the exhaust door.

Technological background

When there is no particular problem for fixing the module on the basis of the watch movement, in particular on the plate, by a vertical translation for meshing a first mobile module with a second mobile pivoted in this base, the module is generally positioned by two feet (or pins) machined or arranged in the base, which penetrate into two respective holes machined in a plate or a module bridge. Once positioned, the module is fixed by at least one screw to the base. Given the manufacturing tolerances for the feet, the holes and the bearings of the first and second mobiles in various parts of the blank, an approximate positioning of the module and a significant variation in the spacing of these first and second mobiles are obtained. This poses a real problem for the movement of the watch movement because a non-optimal meshing of the first and second mobiles decreases the yield and causes a variation thereof. The amplitude of the balance is generally decreased and the accuracy of the step is affected. In this respect, a precise and well-defined meshing between the cog and the exit of an exhaust door is particularly important.

In general, positioning the module by a simple vertical translation is not possible. A solution to this particular problem is given in particular in documents CH-578 203 / US-3,802,183 and CH-581,342 / US-3,945,197. These documents propose a mounting of an exhaust door by a vertical translation to arrange it in a guide hole of the exhaust holder on a foot of the plate (pin or cylinder threaded inside for a fixing screw) around which he can turn. Then, the exhaust carrier is rotated until two respective parts of the exhaust carrier and the rest of the movement abut against each other. In the first document, it is expected that a column (pin) of the exhaust-holder comes to bear against a side wall of a bridge in which the second wheel rotates with which the exhaust pinion must mesh. In the second document, it is expected that a zone of an exhaust-door plate comes to bear against a deck mounted on the plate. In both cases, the problem of the various manufacturing tolerances which vary the spacing of the exhaust pinion and the second wheel remains intact.

In Figs. 1 to 3 is shown a movement in which is mounted an exhaust holder 2 on a plate 4 according to the technique mentioned above. The escapement wheel 6 is pivotally mounted between a lower plate 8 and an upper deck 10 of the exhaust port, just as the rocker 12. In FIG. 1, the exhaust carrier is mounted on a foot or, as shown, on an internally threaded cylinder 16 around which it can rotate to be brought by a horizontal rotation in a final position shown in FIGS. 2 and 3. In this final position, the pinion 18 of the escapement engages with a wheel 14 of the train mounted on the plate. To maintain the exhaust door in its final position, two fixing screws are provided, the first being screwed into the cylinder 16 and the second being screwed into a threaded hole 20 of the plate through a frustoconical hole 22 provided in the upper deck 10. The mounting tolerances of the escapement wheel and the wheel 14 respectively in the exhaust holder and on the plate do not allow to obtain a precise and predetermined spacing. In addition, mounting the exhaust door on the plate has a significant tolerance that greatly increases the problem. Thus, the penetration of the gear pinion 18 into the toothing of the wheel 14 is not precisely determined and has an uncontrolled variable character which negatively influences the operation of the exhaust.

In general, when a module, defining a distinct unit with at least one first pivoting mobile in this module, is arranged on a basis of the watch movement and that the first mobile must mesh with a second mobile pivoting on the base there is a problem that the distance between the first and second mobiles varies around the optimum distance; which affects the smooth running of the watch movement. Indeed, the meshing between the first and second mobile is pejorated by many manufacturing tolerances; this particularly with the planned modular construction. Thus it is difficult to obtain a predetermined distance.

Summary of the invention

The present invention aims to overcome the problem of variable spacing randomly mentioned above in a modular construction.

For this purpose, the present invention relates to a watch movement comprising a module, provided with a first mobile meshing with a second mobile pivoting in a base on which this module is mounted, and positioning means of the module on the base. The positioning means are formed by an eccentric whose profile / periphery at least defines for the most part an Archimedean spiral or an optimized Archimedean spiral, this eccentric being arranged in such a way that it makes it possible to adjust the spacing between the first and second movable when rotated about the geometric center of said Archimedes spiral or said optimized Archimedean spiral. Preferably, the eccentric is calibrated.

The invention also relates to a method of adjusting the distance between a first watch mobile, pivotally mounted in a module which is rotatable about a geometric axis relative to a base on which it is mounted, and a second watch mobile pivoting on said base. The steps of this process are given in appended claim 6.

In a particular embodiment of the invention, the module is an exhaust door, the first mobile being the exhaust pinion and the second mobile being a wheel of the gear mounted on a plate defining the base.

Other particular features of the invention will be described below in the detailed description of the invention.

Brief description of the drawings

The invention will be described below with the aid of the accompanying drawings, given by way of non-limiting examples, in which: Figure 1 is a top view of a movement of the prior art on which is mounted an exhaust door, the latter being in an initial position of its assembly in the movement; Fig. 2 is a top view of the movement of FIG. 1with the exhaust holder in a final position; Fig. 3 is a sectional view along the line III-III of FIG. 2; Fig. 4 is a partial schematic top view of an embodiment of a watch movement in which is mounted an exhaust door according to the invention, the latter being in an initial position; Fig. 5 is a view similar to that of FIG. 4with the exhaust door in an intermediate position of its assembly; and Fig. 6 is a view similar to that of FIG. 4with the exhaust port in a final position of its assembly.

Detailed description of the invention

With the help of Figs 4 to 6, will be schematically described below a clockwork of the type described above with the help of Figs 1 to 3, but incorporating the present invention. The watch movement 30 is partially represented. On the one hand, there is shown the seconds wheel 32 which is pivotally mounted between the plate 4 and a bridge 34 and, on the other hand, an exhaust door 36 carrying an escape wheel, of which only the exhaust pinion 18 is represented. This is sufficient to describe the present invention.

According to a first embodiment of the method of adjusting the center distance L between a first watch mobile 18, pivotally mounted in a module 36 which is capable of being rotated about a geometric axis 38 relative to a base 4 on which it is mounted, and a second mobile watch 32 pivoting on the base, it is provided according to the invention to arrange on the base an eccentric 40 whose periphery 42 defines at least on its major part a spiral of Archimedes or an optimized Archimedean spiral. This process comprises the following steps:

A) Mounting the module 36, in particular an exhaust-holder, on the base 4 in an initial position (FIG 1) in which the first and second mobiles do not mesh, so that this exhaust-holder can, before it is possibly fixed rigidly to this base, rotate about a geometric axis 38 and a first lateral surface 48 of this module, distant from this geometric axis, can bear against the eccentric 40 on a certain angular distance when the eccentric is turned on itself, in particular with the aid of a screwdriver inserted in the slot 44 of this eccentric frictionally mounted on an axis 46 centered on the center of the spiral of Archimedes or the optimized Archimedean spiral;

B) Rotating the module about the geometric axis 38 until the toothing 50 of the first mobile 18 enters the toothing 52 of the second mobile 14 and abuts against the second mobile (Figure 5);

C) Angular positioning of the eccentric 40 so that it is in abutment against the side surface 48 of said module with the first and second movable in the relative position resulting from step B) above (FIG. 5);

D) Following step C), rotating the eccentric over an angular distance substantially corresponding to a determined translation of the first mobile relative to the second mobile and maintaining the lateral surface 48 in abutment against the eccentric, of in such a way as to increase the center distance L by partially withdrawing the toothing 50 from the first mobile of the toothing 52 of the second mobile substantially over a determined distance (FIG 6).

In the embodiment shown in Figs 4 to 6, the module 36 is an exhaust door, the first mobile 18 is the exhaust pinion and the second mobile 14 is a wheel 32 of the gear mounted on a platinum 4 defining said base. In a particular variant, the wheel 32 is the seconds wheel.

According to the invention, the lateral surface 42 of the eccentric 40 forming its periphery substantially defines an Archimedean spiral in a plane perpendicular to its axis of rotation. The Archimedean spiral is the polar equation curve R = P θ where R is the radius in the center and θ is the angle traveled from the origin, that is to say the center of the spiral. The parameter P can be chosen according to the particular configuration and the value of the withdrawal intended to optimize the meshing of the two mobiles. It can have a positive or negative mathematical sign. Note that the eccentric 40 corresponds to a negative sign. The spiral thus has a pitch of P-2π and has a remarkable characteristic, namely the fact that its distance to the center always increases by the same value for a given increase of the angle θ whatever the initial value θ0. This has the consequence that a rotation of the eccentric of a given angle corresponds to a determined increase of the radius R whatever the initial position of the eccentric. The invention takes advantage of this particular feature. When it is mentioned here that the lateral surface of the eccentric defines an Archimedean spiral, it is understood that it corresponds to a turn of such a spiral, for example the tenth or the twentieth. In an improved variant, the Archimedes spiral is optimized because the center of this spiral is distinct from that of the two mobiles and the support surface of the module against the eccentric is not always perpendicular to the direction of rotation (direction tangential) of this module. The Archimedes spiral is thus optimized by calculation as a function in particular of the positions of the two mobiles, the position of the eccentric and the bearing surface of the module against this eccentric in order to have the linear characteristic provided between angle of rotation of the eccentric and the variation of the distance between the two mobiles.

The method of the invention therefore proposes to insert the teeth of the two mobiles in question until the mobile abut against each other. This defines a particular position that is not influenced by manufacturing tolerances. In this particular position, the center distance is essentially defined by the dimensions of the two mobiles that mesh. It will be noted that the lateral play of the mobiles in their respective bearings has the consequence that the two mobiles are not exactly in their free position. This phenomenon can be taken into account when determining the angular distance involved in step D) of the method according to the invention described above.

The angle of rotation of the eccentric 40 corresponds to a determined translation of said first mobile relative to said second mobile, and this that is the initial position of the eccentric when the two mobile are in abutment. Thus, this determined translation used to optimize meshing is freed from the various manufacturing tolerances with the exception of manufacturing tolerance of the eccentric. This follows from the specific profile provided for the periphery of the eccentric. In a preferred variant, the eccentric is calibrated so that the angle of rotation necessary to obtain the aforementioned determined translation corresponds to a predetermined angle.

To properly maintain the module, in particular its lateral surface in contact with the eccentric, bearing against this eccentric during the controlled removal of the toothing 50 of the first mobile of the toothing 52 of the second mobile, a spring 56 is provided in a variant of the method of the invention. This spring is preferably mounted after bringing the exhaust holder on the plate and bringing it to a position where the two wheels are in contact. Alternatively, to gently bring the two mobile abutment, we can use the eccentric turning in the direction that decreases the distance between the two mobiles. In another variant, once the two movers abut against each other, the eccentric 40 is angularly positioned so that it is in abutment against the lateral surface 48 of the module 36. In this configuration it has an initial position for example as shown in FIG. 5. Next, the practitioner or an automaton turns the eccentric in the direction that moves the first mobile from the second mobile.

The axis of the eccentric will preferably be arranged as a function of the dispersion of the manufacturing tolerances so that the point or the zone of contact of this eccentric with the lateral surface 48 of the module 36 is located, if possible, substantially in a predefined area of the turn defined by the periphery of the eccentric. To do this, we will take into account the maximum tolerance at the lateral bearing surface 48 in the intermediate position where the two mobiles bear against each other relative to the eccentric mounted on the plate 4 and also the direction in which the eccentric is rotated to effect controlled and predetermined shrinkage. As an example in the case of an exhaust door, the expected withdrawal is 0.05 mm to ensure proper operation of the movement. If the maximum tolerance for positioning the axis of the eccentric relative to the contact surface of the exhaust carrier is, for example, +/- 0.075 mm, the pitch of the selected hairspring must be at least 0.2 mm at the withdrawal of 0.05 mm and the maximum variation of 0.15 mm in the relative positioning of the eccentric with the module. Since the angular distance for the withdrawal is always in the same direction, the theoretical position of the axis of the eccentric is provided so that in the theoretical position of contact with the module in its aforementioned intermediate position is at a corresponding angular distance. to an increase of 0.075 mm since the recess 58 around the eccentric in the direction of rotation away from the first mobile of the second mobile. Thus one ensures to be able to perform the rotation of the eccentric to perform the translation of 0.05 mm for the purpose of removal in all cases. In the example given, the expected shrinkage advantageously corresponds to a 90 ° angle, which a practitioner can perform approximately easily by a simple observation of the initial position of the slot 44 on the eccentric in the intermediate position and a visual identification of the final position in which the eccentric must be brought; namely here at the perpendicular of the initial position. Note that, because of the recess 58, we will preferably choose a spiral pitch a little higher than the limit case.

In a second embodiment of the method of the invention (not shown), the eccentric is mounted in the module 36 and is integral therewith. In this case, the lateral surface against which this eccentric is supported is that of a portion secured to the base 4. The method of adjusting the distance between the two mobiles remains similar to that of the first embodiment previously described. . This is a technical reversal that the person skilled in the art will easily conceive.

In a preferred embodiment where it is intended to rigidly fix the module in its final position by at least one fixing screw, the upper bridge has an oblong hole 62 in front of which is located a threaded hole 64 in the plate 4. The exhaust door is thus fixed in the final position by means of a flat head screw 76 through the oblong hole. The tapped hole can also be provided in a pin that fits partially into the oblong hole. At the axis of rotation 38 of the exhaust carrier is also provided a tapped hole 66 coaxial with this axis of rotation for a second fastening screw 78.

It will be noted that the method of adjusting the distance according to the invention can also be achieved by an eccentric arranged temporarily on the base or on the module, in particular by means of a tool comprising the eccentric of the invention. The tool and the base or module then comprise complementary means for positioning the tool at a given location and to rotate the tool accurately to achieve the intended adjustment, especially around a geometric axis passing through the center Archimedean spiral or Archimedean spiral optimized.

The invention also relates to the clockwork 30 arranged to implement the method of adjusting the meshing of two mobiles described above. This watch movement comprises a module 36 provided with a first mobile 18 meshing with a second mobile 32 pivoting on a base 4 on which is mounted the module. This module, before it is optionally fixed rigidly to the base, is mounted on this base so that it can rotate horizontally about a geometric axis 38. In the embodiment shown in Figs 4 to 6, a foot or a pin 66 of the base is arranged in a hole of the module 36. According to the invention, the movement comprises positioning means formed by an eccentric 40 whose periphery 42 defines at least a major part of a spiral Archimedes. Preferably, the eccentric is calibrated. The choice of the Archimedean spiral has been explained previously.

A lateral surface 48 of the module 36, distant from the geometric axis 38, is likely to be pressed against the eccentric over a certain angular distance when it is turned on itself. In particular, this lateral surface can be pressed against the eccentric at least when the latter is turned between an intermediate position, in which the two mobiles 18 and 32 abut against each other with their respective teeth that penetrate each other. , and a final position in which these two mobiles are spaced from each other by a given distance to release them and increase the efficiency of the meshing of the two mobiles. The lateral surface 48 is situated in a first zone opposite, relative to a geometric plane 70 defined by the parallel axes of rotation 72 and 74 of the first and second mobiles, to a second zone in which the geometric axis 38 is located. L between these two axes of rotation defines the center distance which is adjusted according to the invention by turning the eccentric substantially over a given angular distance, corresponding to a determined translation of the first mobile relative to the second mobile, from a particular position in which the toothing of the first module penetrates to the maximum the toothing of the second mobile. This particular position has the advantage of being determined only by the dimensions of both mobiles and to overcome manufacturing tolerances. With the eccentric according to the invention, it is possible to make a determined withdrawal to optimize the relative position of the teeth of the two mobiles.

As already mentioned, the present invention is particularly useful when the module is an exhaust door, the first mobile being the exhaust pinion and the second mobile being a wheel of the gear mounted on a plate defining said base. In general it is the last wheel of the wheel, especially the seconds wheel.

Claims (10)

A watch movement (30) comprising a module (36), provided with a first mobile (18) meshing with a second mobile (32) pivoting on a base (4) on which said module is mounted, and means positioning the module on said base, characterized in that said positioning means are formed by an eccentric (40) whose periphery (42) defines at least a large part of an Archimedean spiral or an optimized Archimedean spiral, this eccentric being arranged in such a way that it makes it possible to adjust the center distance (L) between the first and second mobiles when it is turned around the center (46) of said Archimedes spiral or the optimized Archimedean spiral . 2. Timepiece movement according to claim 1, characterized in that said eccentric is substantially calibrated. 3. Watchmaking movement according to claim 1 or 2, characterized in that said module, before it is optionally fixedly fixed to said base, is rotatable about a geometric axis (38) and in that that a lateral surface (48) of this module, distant from this geometric axis, is likely to remain supported against said eccentric, integral with said base, over a certain angular distance when this eccentric is turned around the center (46) of said spiral of Archimedes. 4. A watch movement according to claim 3, characterized in that said lateral surface (48) is located in a first opposite zone, relative to a geometric plane (70) defined by the parallel axes of rotation (72, 74) of the first and second mobiles, to a second zone in which said geometric axis is located. 5. A watch movement according to any one of the preceding claims, characterized in that said module is an exhaust holder, said first mobile being the exhaust pinion and said second mobile being a wheel of the train mounted on a plate defining said base. 6. A method of adjusting the distance (L) between a first watchmobile (18), pivotally mounted in a module (36) which is rotatable about a geometric axis (38) relative to a base ( 4) on which it is mounted, and a second clock mobile (32) pivoting on said base, this method being characterized in that it is intended to arrange permanently or temporarily on the base or on the module an eccentric (40). ), the periphery (42) of which at least for the most part defines an Archimedean spiral or an optimized Archimedean spiral, and in that it comprises the following steps: A) mounting the module on said base so that it can, before it is possibly fixed rigidly to this base, rotate about said geometric axis and a lateral surface (48) of this module or a integral with said base, depending on whether the eccentric is respectively integral with the base or the module, can bear against said eccentric over a certain angular distance when the eccentric is rotated around the center of said spiral Archimedes or the Archimedean spiral optimized; B) Rotating said module about said geometric axis until the toothing of the first mobile penetrate the toothing of the second mobile and abut against this second mobile; C) angular positioning of said eccentric so that it bears against said lateral surface with the first and second mobiles in the relative position resulting from step B); D) following step C), rotation of said eccentric over an angular distance substantially corresponding to a determined translation of said first mobile relative to said second mobile so as to increase said distance substantially by a determined distance by partially removing the toothing of the first mobile the toothing of the second mobile, and maintaining said lateral surface bearing against said eccentric. 7. Method according to claim 6, characterized in that said eccentric is calibrated so that said angular distance corresponds to a predetermined angle. 8. The method of claim 6 or 7, characterized in that said lateral surface is held in abutment against said eccentric by a spring (56). 9. Method according to any one of claims 6 to 8, characterized in that said module is an exhaust holder, said first mobile being the exhaust pinion and said second mobile being a gear wheel mounted on a plate defining said based. 10. Method according to any one of claims 6 to 9, characterized in that, following step D), said module is fixed rigidly to said base by at least one fixing screw (76).