Play-eliminating gear for clock mechanisms

Abstract

The present invention relates to a movement gear (1) for integrating in a movement, or in a clock, in particular a gear wheel for a movement gear train of a chronograph movement of a clock, wherein the gear has a pinion (1.1), which defines an axis of rotation (1.1.1) of the gear, a first gear element (1.2) with a first toothing (1.2.5) that is arranged at its circumference, is formed in a rigid manner and lies in a first plane perpendicular to the axis of rotation, and a second gear element (1.3) with a second toothing (1.3.4) that is arranged at its circumference and is coaxial with the first toothing (1.2.5) in a second plane parallel to the first plane, wherein the pinion (1.1), the first gear element (1.2) and the second gear element (1.3) are fixedly attached to one another and the second toothing (1.3.4) is arranged in a manner offset through an angular range relative to the first toothing (1.2.5). The gear is characterised in that said second toothing (1.3.5) is not in the form of a rigid toothing, wherein the second toothing element (1.3) has a spring arm wheel (1.3.2) and elastically deformable spring arms (1.3.2) which are each attached to said spring arm wheel (1.3.1) at their inner end directed towards the axis of rotation and carry at least one tooth (1.3.3) of the second toothing (1.3.4) at their outer end directed towards the gear circumference, such that each tooth (1.3.3) or at least some of the teeth (1.3.3) of the second toothing (1.3.4), when acted upon, can be resiliently deflected independently of the teeth (1.3.3) of the second toothing (1.3.4) that are carried by the other spring arms (1.3.2). The invention also relates to a movement gear train, to a movement, and to a clock having such a gear.

Description

[0001] Backlash-cancelling gear for clock mechanisms

[0002] Field of the invention

[0003] The present invention relates to a clockwork gear for integration into a clockwork movement, or into a clock, in particular to a transmission gear for a clockwork gear train of a chronograph clockwork movement of a clock, preferably a wearable watch such as a wristwatch, wherein the gear has a pinion which defines an axis of rotation of the pinion, a first gear element with a first toothing arranged on its circumference, which is rigid and lies in a first plane perpendicular to the axis of rotation, and a second gear element with a second toothing arranged on its circumference, which lies coaxially to the first toothing in a second plane parallel to the first plane, wherein the pinion, the first and the second gear element are fixedly attached to one another and the second toothing is arranged offset by an angular range relative to the first toothing.The invention also relates to a clockwork gear train, to a clockwork and to a clock having such a gear.

[0004] Background of the invention and prior art

[0005] Gear wheels for clockwork mechanisms are an indispensable component of watches and are therefore frequently described in the prior art. In particular, gear wheels are also known from the prior art whose design is intended to reduce the play that occurs between the gears involved during operation of the clockwork mechanism.

[0006] For example, single-piece gear wheels are known in which each tooth is formed by several very narrow lamellae and is thus deformable. However, this results in very small dimensions with respect to these lamellae and corresponding difficulties in the manufacture and handling of such wheels. This is particularly true for gear wheels with a large number of teeth, for example, gear wheels in a chronograph gear train, insofar as an increase in the number of teeth reduces the tooth pitch angle, so that beyond a certain minimum tooth pitch angle, which depends on the available manufacturing processes, the production of such thin lamellae is no longer possible.

[0007] Document EP 2 677 372 discloses a backlash-reducing clockwork wheel having a toothing lying on one plane comprising a sequence of pairs of identical teeth each formed by a first and a second flexible tooth arm, the distances between the first and second teeth within a pair being different from those distances outside such a pair, and the teeth having abutment surfaces each directed towards the teeth of the adjacent pair of teeth to provide support in the event of an impact.

[0008] European patent EP 2 877 900 also describes a backlash-reducing clockwork wheel with a single-plane, flexible toothing. The toothing is formed by a plurality of flexible spokes, each carrying a tooth and engagement means that can interact with the engagement means on an adjacent spoke by means of tensile or shear contact. Although the clockwork wheels according to documents EP 2 677 372 and EP 2 877 900 have only a single plane of teeth, these wheels have a comparatively complex structure due to the stop surfaces and the engagement means, respectively, which complicates their manufacture and handling.Document US 4,437,356 discloses a gear suitable for use in, among other things, watchmaking. It is made in one piece from an elastic material and has two planes of teeth that alternately mesh with the teeth of another gear. Two adjacent teeth on each plane are spaced apart from each other, so that the teeth on both planes of the gear are elastically deformable. This allows for damping and thus noise reduction when the gear meshes with another gear.

[0009] Document EP 2 172 815 describes a gear train for watches with at least one pair of gears, each having parallel axes of rotation and at least two coaxially superimposed, annular, rigid toothings that are rotated relative to each other by an angular range and that alternately mesh with each other. In the preferred embodiment of the gear train, each gear of the at least one pair of gears has two such rigid toothings, each offset from each other by half the width of the tooth pitch.

[0010] Document EP 3 042 250 discloses a rotary part for watches, designed as a one-piece workpiece, with backlash adjustment. The rotary part comprises a hub, a first toothed ring rigidly connected to the hub, and a second toothed ring connected to the hub by at least one elastically deformable arm, which, in the rest position, is offset by an angular range relative to the first toothed ring. The two toothed rings are rigid components, and both the number and shape of the teeth on the first and second toothed rings can be the same or different. The backlash-adjusting watch wheels according to documents US 4,437,356, EP 2 172 815, and EP 3 042 250 have two planes of teeth, in particular either two elastic or two rigid annular toothings, which is disadvantageous in terms of energy loss during torque transmission.

[0011] It can therefore be stated that the prior art describes a multitude of approaches to reducing backlash in clockwork gear trains, whereby these approaches apply both to gears with only one toothing on a single plane and to gears with toothing on two or more planes. Despite the multitude of approaches described in the prior art, there is still a need for a solution that can overcome or at least mitigate the above-mentioned limitations and disadvantages, particularly for gears with a high number of teeth.

[0012] Object of the invention

[0013] The aim of the present invention is to create a backlash-eliminating or at least backlash-reducing clockwork gear that is as simple as possible in terms of construction, as practical in terms of manufacture and assembly, robust in terms of handling, and flexible in terms of usability. At the same time, the energy loss during torque transmission using such an improved gear should be kept as small as possible. The improved backlash-eliminating gear should be particularly suitable for driving chronograph mechanisms in wristwatches, but also generally for driving other clock mechanisms.

[0014] Summary of the inventive solution

[0015] The present invention therefore has as its subject matter a generic gearwheel which is characterized by the features mentioned in the characterizing part of claim 1, as well as a gear train according to claim 12, a clockwork according to claim 15 and a corresponding clock according to claim 17, which have such a gearwheel.To achieve the aforementioned objectives, the subject matter of the invention is characterized in particular in that said second toothing of the gear is designed as a non-rigid toothing, wherein the second gear element has a spring arm wheel and elastically deformable spring arms, which are each attached to said spring arm wheel at their inner end directed towards the axis of rotation and carry at least one tooth of the second toothing at their outer end directed towards the gear circumference, such that each tooth or at least some of the teeth of the second toothing can be resiliently deflected when subjected to a load, independently of the teeth of the second toothing carried by other spring arms.

[0016] Preferably, said first toothing and said second toothing have the same number of teeth, wherein the teeth of said second toothing are designed as half teeth in a particularly preferred embodiment.

[0017] Advantageously, the first and second gear elements have positive-locking alignment elements that allow the first and second gear elements to be secured in at least one predefined relative position. The positive-locking alignment elements are preferably implemented by means of pins in one component and corresponding alignment openings provided in the other component.

[0018] In a clockwork gear train according to the invention, at least one of the gear wheels of the gear train consists of such a gear. Preferably, the gear train comprises a third wheel, a second wheel driven by the third wheel, a second wheel driven by the third wheel, and a chronograph pinion of a chronograph mechanism of the watch, also driven by the third wheel. Said third wheel is part of a second wheel unit consisting of a backlash-eliminating or at least backlash-reducing gear according to the invention.

[0019] A clockwork according to the invention and a corresponding clock have such a gearwheel or such a clockwork gear train.

[0020] Further features and advantages of a gear according to the invention, or of a clockwork gear train according to the invention and of a corresponding clockwork and of a corresponding clock, emerge from the dependent claims and from the description which sets out the invention in detail below by means of the attached figures.

[0021] Brief description of the figures

[0022] The attached figures show, by way of example, several embodiments of a gear and a clockwork gear train according to the present invention.

[0023] Figures 1a and 1b are exploded views from above and from below, respectively, of a first embodiment of a gear according to the invention.

[0024] Figures 2a and 2b are perspective views from above and below, respectively, of the same embodiment of a gear according to the invention in the assembled state, but without the cover plate shown in Figures 1a and 1b for better visibility of the components of the second gear element; Figures 2c and 2d show views from above and below, respectively, of the gear shown in Figures 2a and 2b; Figure 2e shows a cross-section through the gear according to the invention along the line AA shown in Figure 2c.

[0025] Figures 3a, 3b, 3c, 3d, 3e and 3f show schematic views of further alternative embodiments of a gear according to the invention.

[0026] Figure 4a shows a perspective view of a clockwork gear train according to the invention, with some parts of the gear train not shown or only partially shown or shown schematically for better understanding; Figures 4b and 4c show views from above and below, respectively, of the gear train shown in Figure 4a.

[0027] Detailed description of the invention

[0028] In the following, the invention will now be described in detail with the aid of the aforementioned figures, wherein modifications and additional embodiments not shown in the figures will also be explained below. The gear according to the invention is illustrated by way of example in particular in connection with a chronograph mechanism well known to those skilled in the art in the watchmaking field, although such a gear can also be used in conjunction with other watch mechanisms. The following description, mainly within the context of a chronograph mechanism, is therefore not intended to represent any limitation on the scope of application of the invention. Figures 1a and 1b show schematic and exemplary exploded views from above and from below, respectively, of a first preferred embodiment of a gear 1 according to the invention, which is suitable for integration into a watch movement gear train and into a watch movement, or into a watch.This is in particular a gear wheel for a clockwork gear train of a chronograph movement of a watch, but it can also be a gear wheel for another clockwork gear train, such as a gear wheel for driving a continuous display, i.e. a non-jumping display, for example for driving any continuous counter of a watch such as a small seconds display, a rattrapante mechanism, a day-night display and / or a moon phase display.

[0029] As can be seen from Figure 1a, the gear 1 in this preferred embodiment has a pinion 1.1 defining a rotational axis 1.1.1 of the gear, a first gear element 1.2 with a first toothing 1.2.5 arranged on its circumference, which is rigid and lies in a first plane perpendicular to the rotational axis, and a second gear element 1.3 with a second toothing 1.3.4 arranged on its circumference, which lies coaxially to the first toothing 1.2.5 in a second plane parallel to the first plane. The pinion 1.1, the first gear element 1.2, and the second gear element 1.3 are firmly attached to one another, which will be explained in more detail below. The first - 1.2 and the second gear element 1.3 have noticeably the same pitch circle radius, whereby the tip circle of the second gear element 1.3 is the same as or, to protect its teeth 1.3.4, slightly smaller than that of the first gear element 1.2, and the said first toothing 1.2.5 and the said second toothing 1.3.4 have the same number of teeth. As can be seen in particular from Figures 2a, 2b, 2c and 2d, in this preferred embodiment the second toothing 1.3.4 is arranged offset rearward by an angular range relative to the first toothing 1.2.5, counter to the direction of rotation of the gear 1, i.e. the rear tooth flank of the teeth 1.3.3 of the second toothing 1.3.4 is - viewed in the direction of rotation of the gear shown by arrows in Figures 2a and 2b and in its rest position - offset rearward by a certain angle compared to the rear tooth flank of the teeth 1.2.4 of the first toothing 1.2.5. As will be explained in more detail below, this allows each tooth 1.3.3 or at least a part of the teeth 1.3.3 of the second toothing 1.3.4 to be deflected resiliently when subjected to a load in the direction of rotation of the gear 1, ie forwards.

[0030] In an alternative embodiment of a gear 1 according to the invention, not shown in the figures, the second toothing 1.3.4 can be arranged offset forwards by an angular range relative to the first toothing 1.2.5 in the direction of rotation of the gear 1, i.e. the front tooth flank of the teeth 1.3.3 of the second toothing 1.3.4 is - again viewed in the direction of rotation of the gear and in its rest position - offset forwards by a certain angle compared to the front tooth flank of the teeth 1.2.4 of the first toothing 1.2.5. This allows each tooth 1.3.3 or at least some of the teeth 1.3.3 of the second toothing 1.3.4 to be resiliently deflected when subjected to a load opposite to the direction of rotation of the gear 1, i.e. to the rear.

[0031] The first gear element 1.2 is preferably designed in one piece as a conventional gear, i.e. it can have a hub 1.2.1, a wheel rim 1.2.3 and wheel arms 1.2.2 which connect the hub 1.2.1 to the wheel rim 1.2.3, wherein the wheel rim 1.2.3 carries the rigid teeth 1.2.4 which form the first toothing 1.2.5 on its circumference. The hub 1.2.1 has a central receiving opening whose inner shape complements the outer shape of the pinion 1.1, so that the gear element 1.2 can be riveted onto the pinion 1.1 in the usual way. The number and shape of the teeth 1.2.4 of the first toothing 1.2.5 are not important in the context of this description and are determined beforehand depending on the function of the gear, i.e. depending on the application of the associated gear train.

[0032] The gear 1 according to the invention is characterized in particular in that the said second toothing 1.3.4 is designed as a non-rigid toothing. It should be noted in this regard that the terms "rigid" and "non-rigid" are used in this description in connection with the first toothing 1.2.5 and the second toothing 1.3.4 to the effect that the distance between the teeth of the first toothing 1.2.5 can be regarded as constant, i.e., rigid, and that the teeth of the second toothing 1.3.4 can be deflected at least partially independently of one another, so that the distance between these teeth, or at least between parts or sections of these teeth, cannot be regarded as constant, i.e., not rigid. For this purpose, the second gear element 1.3 has a spring arm wheel 1.3.1 and elastically deformable spring arms 1.3.2. The spring arm wheel 1.3.1 itself can also be designed conventionally, ie it can - similar to the first gear element 1.2 - preferably be formed in one piece as a conventional wheel and thus have a spring arm wheel hub with a central opening, a spring arm wheel rim, and wheel arms that connect the spring arm wheel hub to the spring arm wheel rim. Like the first gear element 1.2, the spring arm wheel 1.3.1 could in principle also be implemented as a disc wheel, although this is not preferred for weight reasons. The elastically deformable spring arms 1.3.2 are each firmly attached to said spring arm wheel 1.3.1 at their inner end directed towards the rotation axis 1.1.1 and carry at least one tooth 1.3.3 of the second toothing 1.3.4 at their outer end directed towards the gear circumference. The teeth 1.3.3 of the second toothing 1.3.4, like the teeth 1.2.4 of the first toothing 1.2.5, are preferably made of a non-deformable or only slightly deformable material. The second gear element 1.3 with the spring arm wheel 1.3.1, the elastically deformable spring arms 1.3.2 and the teeth 1.3.3 located thereon, which form the second toothing 1.3.4, is preferably also manufactured in one piece.

[0033] Each tooth 1.3.3 or at least a part of the teeth 1.3.3 of the second toothing 1.3.4 can, due to the above-described structure of the gear 1, when subjected to a load, which occurs when a tooth of a wheel meshing simultaneously with the two toothings 1.2.5 and 1.3.4 of the gear 1 engages, independently of the teeth 1.3.3 of the second toothing 1.3.4 carried by other spring arms 1.3.2, be resiliently deflected in a direction tangential to the circumference, which in the preferred embodiment shown in Figures 2a to 2e is directed in the direction of rotation of the gear and which, in an embodiment not shown in the figures, is opposite to the direction of rotation of the gear, until the said tooth of the wheel meshing simultaneously with the two toothings 1.2.5 and 1.3.4 of the gear 1 engages the corresponding rigid tooth 1.2.4 of the first toothing 1.2.5 and engages with it. The teeth 1.3.3 of the second toothing 1.3.4, due to their attachment to elastically deformable spring arms 1.3.2, therefore allow the play between the gear 1 and the wheel not shown in Figures 1a and 1b and 2a to 2e, whose teeth simultaneously mesh with the two toothings 1.2.5 and 1.3.4 of the gear 1, to be eliminated or at least reduced. The gear 1 preferably drives the wheel, which is meshed with its two toothings 1.2.5 and 1.3.4, but the use of the gear 1 as a driven wheel is also possible.

[0034] In the configuration shown in Figures 1a and 1b and 2a to 2e

[0035] In one embodiment of the gear 1, the second toothing 1.3.4 of the second gear element 1.3 has an elastically deformable spring arm 1.3.2 for each of its teeth 1.3.3, wherein each elastically deformable spring arm 1.3.2 is preferably oriented substantially radially. Alternatively, a different shape of the elastically deformable spring arms 1.3.2, such as curved or inclined at a certain angle to the radial direction, would be possible.

[0036] In further alternative embodiments, said second toothing 1.3.4 can have at least one elastically deformable spring arm 1.3.2 for each part of adjacent teeth 1.3.3 located on a circular arc-shaped section 1.3.5 of its circumference, wherein each of said circular arc-shaped sections 1.3.5 preferably carries between 2 and 8 teeth 1.3.3 of the second toothing 1.3.4, particularly preferably between 2 and 6 teeth 1.3.3, and wherein the elastically deformable spring arm(s) 1.3.2 are attached centrally, at the ends of each circular arc-shaped section 1.3.5 or elsewhere along the circular arc-shaped section 1.3.5 and can have different arm thicknesses and shapes. As schematically shown in Figures 3a and 3b, it is possible, for example, for each elastically deformable spring arm 1.3.2 to be appreciably radially oriented and to carry a circular arc-shaped section 1.3.5 with two teeth 1.3.3 of the said second toothing 1.3.4.Figures 3c and 3d show a further exemplary embodiment of the second gear element 1.3, in which each elastically deformable spring arm 1.3.2 is oriented at a specific angle to the radial direction and also carries a circular arc-shaped section 1.3.5 with two teeth 1.3.3 of said second toothing 1.3.4. As a further example, Figures 3e and 3f show an embodiment of the second gear element 1.3, in which each circular arc-shaped section 1.3.5 is carried by two noticeably radially oriented, elastically deformable spring arms 1.3.2 and itself carries several teeth 1.3.3 of said second toothing 1.3.4, five teeth 1.3.3 in the example shown. The circular arc-shaped sections 1.3.5 with the teeth 1.3.3 of the said second toothing 1.3.4 located thereon are in any case resiliently deflectable independently of one another when subjected to stress.Figures 3b, 3d and 3f each show an enlarged section of Figures 3a, 3c and 3e for better illustration.

[0037] Generally, the length L of each elastically deformable spring arm 1.3.2 is in the range of 15% to 75% of the radius R of said second gear element 1.3, preferably in the range of 25% to 50% of the radius R of the second gear element 1.3. The width B Fof each elastically deformable spring arm 1.3.2 lies in the range from 5% to 80% of the width B2 of the teeth 1.3.3 of said second toothing 1.3.4, preferably in the range from 10% to 40% of the width B2 of the teeth 1.3.3 of the second toothing 1.3.4. The width B2 of the teeth 1.3.3 of said second toothing 1.3.4 carried by the elastically deformable spring arms 1.3.2 lies in the range from 20% to 80% of the width Bi of the teeth 1.2.4 of the first toothing 1.2.5, preferably in the range from 40% to 60% of the width Bi of the teeth 1.2.4 of the first toothing 1.2.5. Particularly preferably, the teeth 1.3.3 of said second toothing 1.3.4 are designed as half-teeth, as shown in Figures 1a and 1b and 2a to 2e. The thicknesses of the first gear element 1.2 and the second gear element 1.3 are usually in the range of about 0.08 - 0.40 mm, depending on the manufacturing process used, but a gear according to the invention can, of course, also have gear elements of other thicknesses if necessary.

[0038] The first gear element 1.2 and the second gear element 1.3 have positive-locking alignment elements 1.2.2.1, 1.3.1.1, which allow the first gear element 1.2 and the second gear element 1.3 to be secured in at least one predefined relative position to one another. The alignment elements 1.2.2.1, 1.3.1.1 preferably define at least three predefined relative positions to one another. The at least one predefined relative position ensures the centering of the first gear element 1.2 and the second gear element 1.3, and each predefined relative position defines a predetermined angle by which the second toothing 1.3.4 is offset relative to the first toothing 1.2.5.

[0039] The positive alignment elements 1.2.2.1, 1.3.1.1 are in the preferred embodiment shown in the figures by means of at least one on the first gear element 1.2 or alternatively on the spring arm wheel

[0040] 1.3.1 of the second gear element 1.3, preferably by means of two pins 1.2.2.1 mounted on the wheel arms 1.2.2 of the first gear element 1.2, and for each pin 1.2.2.1 at least one, preferably three to seven, alignment opening 1.3.1.1 arranged on the spring arm wheel 1.3.1 of the second gear element 1.3, for example on the spring arm wheel rim of the spring arm wheel 1.3.1, or alternatively on the first gear element 1.2. In the preferred embodiment shown in the figures, a pin 1.2.2.1 is mounted on each of two of the wheel arms 1.2.2 of the first gear element 1.2, and five corresponding alignment openings 1.3.1.1 are provided on the spring arm wheel rim of the spring arm wheel 1.3.1 for each of these pins 1.2.2.1, so that five relative positions are predefined for the fastening of the first gear element 1.2 and the second gear element 1.3.Of course, more or fewer than five positions can also be predefined using corresponding alignment openings 1.3.1.1. This simplifies the manufacture of the gear 1, in that during its assembly, the first gear element 1.2 and the second gear element 1.3 are centered in a first step and pre-assembled in the desired relative position with respect to their angular offset. Then, in a second step, the pre-assembled package consisting of the first gear element 1.2 and the second gear element 1.3 is mounted on the drive 1.1, for example, by riveting.

[0041] In the embodiments of a gear 1 according to the invention shown by way of example in Figures 1a and 1b and 2a to 2e, five different angles of rotation between the first gear element 1.2 and the second gear element 1.3, i.e. five different spring preloads of the elastically deformable spring arms 1.3.2 of the second gear element 1.3, can therefore be set with the same components during its assembly, depending on which of the three marked positions ("N" for nominal position, "-" for less spring preload / reduction in play or "+" for more spring preload / reduction in play) and the two intermediate positions is selected during assembly of the gear. For example, in the case of the number of teeth of tooth sets 1.2.5 and 1.3.4 shown in Figures 1a and 1b and 2a to 2e, the nominal position «N» may have an angular offset of 0.46 ° between the first tooth set 1.2.5 and the second tooth set 1.3.4, which in this case is designed to reduce the play to zero, but requires almost no deformation of the elastically deformable spring arms 1.3.2, while the positions «-» and «+» define an angular offset of 0.26 °, and 0.66 °, respectively, between the first toothing 1.2.5 and the second toothing 1.3.4, which corresponds to a minimum play with almost no load on the spring arms 1.3.2 in the position «-», or a penetration of the meshing teeth with a higher preload on the spring arms 1.3.2 in the position «+».

[0042] As shown in Figures 1a and 1b, in some embodiments, a gear 1 according to the invention can also have a fixedly attached cover plate 1.4 to protect the elastically deformable spring arms 1.3.2, which carry the teeth of said non-rigid, second toothing 1.3.4. The cover plate 1.4 is attached such that the second gear element 1.3 with the elastically deformable spring arms 1.3.2 lies between the first gear element 1.2 and said cover plate 1.4, i.e., the cover plate 1.4 is attached to the second gear element 1.3 on the side opposite the first gear element 1.2. The cover plate 1.4 is preferably also formed in one piece as a conventional wheel, but has no teeth, ie it can have a cover plate hub 1.4.1, a cover plate rim 1.4.3 and cover plate arms 1.4.2, which connect the cover plate hub 1.4.1 to the cover plate rim 1.4.3. The cover plate hub 1.4.1 has a central receiving opening whose inner shape complements the outer shape of the pinion 1.1, so that the cover plate 1.4 can also be riveted onto the pinion 1.1 in the usual way, preferably during the above-mentioned second step during the manufacture of the gear 1. The width of the cover plate ring 1.4.3 is selected depending on the length of the elastically deformable spring arms 1.3.2 so that effective protection of the spring arms 1.3.2 from mechanical influences is guaranteed, without the possibility of the cover plate 1.4 being accidentally involved in the engagement of the gear 1 with the wheel meshing with it. Alternatively, the cover plate 1.4 can be designed like a disc. In any case, the cover plate 1.4 only serves to protect the spring arms 1.3.2 and has no influence on the function of the gear 1, so that it represents an optional component.

[0043] For the sake of completeness, it should also be mentioned that a gear 1 according to the invention can also have a second gear element 1.3 on each side of the first gear element 1.2, in which case the angular offset of the corresponding second toothings 1.3.4 is opposite and therefore the deflection direction of the elastically deformable spring arms 1.3.2 of the second gear element 1.3 located on one side of the first gear element 1.2 is opposite to the deflection direction of the elastically deformable spring arms 1.3.2 of the second gear element 1.3 located on the other side of the first gear element 1.2. Such a gear can be used in gear trains that can be operated bidirectionally at least temporarily, for example, during an adjustment process that results in the gear train operating with a direction of rotation of the gears that is opposite to the direction of rotation of the gears during normal operation.Such a gear can accordingly also have two corresponding cover plates 1.4.

[0044] Finally, it should be mentioned that the components of the gear 1, i.e., the pinion 1, the first gear element 1.2 and the second gear element 1.3, as well as the cover plate 1.4, are preferably each manufactured monolithically. They can be manufactured conventionally from steel, by LiGA processes (lithography, electroplating, and molding), preferably from nickel or a nickel-phosphorus compound, by DRIE processes (Deep Reactive Ion Etching), and / or by 3D printing. Alternatively, the components or at least some parts of the gear 1 can be manufactured from a silicon-based material. This material can, for example, be selected from a group of materials comprising monocrystalline silicon (Si) of any orientation, polycrystalline silicon (p-Si), amorphous silicon (a-Si), porous silicon, silicon dioxide (SiO2), and a mixture of silicon and silicon oxide.At least some of the parts made from a silicon-based material, preferably all of the parts made from a silicon-based material, can have a diamond coating or a coating of silicon dioxide (SiO2) on at least part of their surface in order to reduce friction between the parts and increase the wear resistance of the components. These manufacturing processes are all known to those skilled in the art and are therefore not explained in detail here. In light of the above description of the structure of a gear according to the invention, its mode of operation and the resulting advantages compared to the prior art are easily understood. Firstly, in a gear 1 according to the invention, in particular in a gear 1 according to the preferred embodiment shown in Figures 1a and 1b and 2a to 2e, the load from the torque transmission lies almost entirely on the teeth 1.2.4 of the first, rigidly designed toothing 1.2.5, while the teeth 1.3.3 of the second, non-rigidly designed toothing 1.3.4, which are carried by the elastically deformable spring arms 1.3.2, "give way" when the gear 1 and the wheel meshing with it engage, ie are deflected resiliently in or against the direction of rotation of the gear, due to the deformability of the spring arms 1.3.2, which are more or less pre-tensioned by the selectable angular offset between the first toothing 1.2.5 and the second toothing 1.3.4. Depending on the design, this deflection occurs until the desired, preset degree of backlash elimination is achieved, or even until the corresponding tooth of the gear meshing simultaneously with the two tooth sets 1.2.5 and 1.3.4 of gear 1 meets and engages the corresponding rigid tooth 1.2.4 of the first tooth set 1.2.5. In other words, the spring arms 1.3.2 and the teeth 1.3.3 of the second tooth set 1.3 serve.4 is almost exclusively dedicated to bridging the backlash between gear 1 and the wheel meshing with it. The elastically deformable spring arms 1.3.2, i.e., the flexible parts of the second gear element 1.3, are therefore primarily exposed to inertial loads, i.e., comparatively low loads. Compared to previously known backlash-adjusting clockwork wheels, particularly those with flexible teeth formed from several very narrow lamellae, fewer wear problems arise. Since torque is transmitted primarily via teeth 1.2.4 of the first, rigid toothing 1.2.5, there is also less energy loss during torque transmission.In comparison to at least some previously known gears with toothings located on two or more levels, a gear according to the invention also has a lower energy loss during torque transmission because not the entire flexibly designed toothing has to be rotated relative to the rigid toothing, but only one tooth or part of the toothing.

[0045] On the other hand, in a gear according to the invention, particularly in contrast to one-piece flexible gears in which each tooth is divided into several, comparatively delicate lamellae, significantly larger dimensions are possible for the elastically deformable spring arms 1.3.2, which can thus be designed to be more stable on the one hand and which, on the other hand, offer more freedom in terms of their design. The reason for this is that in the embodiments shown in the figures, per tooth

[0046] 1.3.3 of the second toothing 1.3.4 only one elastically deformable spring arm 1.3.2 is required. This applies especially to designs in which the teeth

[0047] 1.3.3 of the second toothing 1.3.4 are distributed over a certain number of said circular arc-shaped sections, since in this case even less than one elastically deformable spring arm 1.3.2 per tooth 1.3.3 of the second toothing

[0048] 1.3.4 is necessary. This makes it possible to apply the invention to gears with a comparatively high number of teeth, for example, gears for chronograph mechanisms. Another advantage is that the teeth 1.3.3 of the second toothing 1.3.4 can, for example, consist of only half a tooth, while in principle almost the entire tooth pitch angle can still be used for the body of the elastically deformable spring arms, which opens up further design freedom. Due to the smaller number of elastically deformable or resilient elements, the options for the length of the elastically deformable spring arms are also significantly more diverse than with one-piece flexible gears with only one toothing on one plane. A gear according to the invention can therefore be designed in a more diverse manner in its construction, is easier to manufacture, and is less sensitive to handling.

[0049] Thirdly, a gear according to the invention, through the positive alignment elements 1.2.2.1, 1.3.1.1 of the first gear element 1.2 and the second gear element 1.3, offers a certain degree of adjustability during assembly, which is nevertheless implemented in a very simple manner, insofar as the positive alignment elements can preferably be implemented by means of pins 1.2.2.1 in one component and corresponding alignment openings 1.3.1.1 provided in the other component. This provides a certain degree of robustness against manufacturing variations, allows for optimization of the flutter behavior of the gear in a given clockwork movement with regard to energy consumption, and enables several options in the range from reduced backlash to no backlash between the meshing gears, depending on the function and application of the gear according to the invention in a given gear train or clockwork.

[0050] In view of the above representation of a gear according to the invention, it is clear that the latter is intended for clockwork gear trains for integration into a clockwork, or rather, into a watch, wherein the corresponding gear train has at least two meshing gears and wherein at least one of the wheels of this gear train consists of a gear 1 according to the invention. The gear 1 according to the invention is preferably the driving wheel, which transmits a torque to a wheel that is meshed with its two toothings 1, 2, 5 and 1, 3, 4. In principle, however, the use of the gear 1 as a driven wheel is also possible.

[0051] A particularly preferred application of a gear according to the invention is its use in a gear train of a chronograph mechanism of a watch, as schematically illustrated in Figures 4a, 4b, and 4c, which show a perspective view as well as top and bottom views of such a watch gear train. Such a gear train according to the invention comprises a large third wheel 2.2 attached to a large third wheel pinion 2.1, which forms the large third wheel unit 2. The large third wheel pinion 2.1 is driven in a known manner by a power source of the watch, preferably by means of a mechanical power source such as a hairspring mounted in a barrel of the watch. The gear train also comprises a small third wheel pinion 1.1 driven by the large third wheel 2.2, which is attached to a small third wheel 1.2, 1.3 and, together with it, forms part of the small third wheel unit 1. Furthermore, the gear train comprises a second-seconds pinion 3 driven by the small third wheel 1.2, 1.3.1, which is attached to the seconds wheel 3.2 and together with it forms the seconds wheel unit 3, as well as a chronograph pinion 4.1, which is also driven by the third wheel 1.2, 1.3.

[0052] Chronograph rotating part 4 of a chronograph mechanism of the watch. The chronograph pinion 4.1 carries a clutch (not shown in Figures 4a to 4c) or is kinematically connected to such a clutch, which clutch allows the chronograph mechanism to be started, stopped, and reset. Since those skilled in the art in the watchmaking field are familiar with such clutches as well as the further structure and functioning of a chronograph mechanism, and this is not relevant to the present invention, it will not be discussed in detail below. It should only be mentioned in principle that the chronograph mechanism can also have a chronograph rattrapante hand or a corresponding rattrapante mechanism. The gear train according to the present invention is characterized in that the said small caseback unit 1 consists of a gearwheel 1 according to the invention and therefore the small caseback wheel 1.2, 1.3 has both the first gear element 1.2 and the second gear element 1.3 of the above-described gear 1, wherein the two gear elements 1.2, 1.3 are connected to the second wheel drive to eliminate play.

[0053] 3.1 and the chronograph pinion 4.1. The power flow in this gear train therefore occurs, as is usual in such a gear train, from the large third wheel 2.2 via the small third wheel 1.2, 1.3 to the seconds wheel pinion 3.1 and from the latter via the escapement / anchor wheel to the escapement, whereby the last two parts are not shown in the illustrations and the preferred direction of rotation of the respective wheels and pinions is only symbolically indicated in Figure 4b by means of arrows. Due to the use of a gear according to the invention, i.e. through the elastic deformation of the elastically deformable spring arms 1.3.2 belonging to the respective meshing teeth, the torque is transmitted via the small third wheel, or rather via the small third wheel unit 1, also to the chronograph pinion 4.1, whereby this torque transmission takes place without "fluttering" of the chronograph pinion.

[0054] 4.1 occurs, although the latter drive is not in the direct power flow.

[0055] In general, a gear according to the invention finds further applications in any gear train comprising a gear wheel and a display drive driven by said gear wheel for driving a continuous display, wherein the display drive preferably serves to drive a counter, a small second display, a rattrapante mechanism driven by a planetary gear, a day-night display and / or a moon phase display, or similar display means. The display means just mentioned also include applications that have a continuous, bidirectional display, for example, power reserve displays, temperature displays, pressure indicators (direct display of air or water pressure) and depth or altitude indicators (display by means of air or water pressure). In this case, the gear train according to the present invention is characterized in that said gear wheel consists of a gear wheel 1 according to the invention.Finally, the present invention relates to a clockwork movement for integration into a timepiece, in particular to a chronograph clockwork movement for integration into a wristwatch, comprising a power source, a gear train, an escapement, and a regulating member, wherein the gear train of the clockwork movement comprises a gearwheel 1 according to the invention or consists of a clockwork gear train according to the invention. Such a clockwork movement preferably has at least one additional clockwork mechanism, in particular a chronograph mechanism, wherein the additional clockwork mechanism is driven by a gearwheel 1 according to the invention or by a clockwork gear train according to the invention. The present invention naturally also relates to a clock with a gearwheel 1 according to the invention, with a gear train according to the invention, or with a clockwork movement according to the invention.

[0056] From the foregoing, it is clear that the above-mentioned advantages of a gearwheel 1 according to the invention are transferred to such a clockwork gear train or clockwork movement, as well as to an associated clock. In addition to a gearwheel with a comparatively simple design, practical manufacture, robust handling, and versatile applicability, the present invention also provides correspondingly improved clockwork gear trains, clockwork movements, and clocks, in particular wristwatches.

[0057] List of reference symbols

Claims

Claims 1. Clockwork gear (1) for integration into a clockwork, or into a watch, in particular a gear for a clockwork gear train of a chronograph clockwork of a watch, wherein the gear comprises a pinion (1.1) defining a rotational axis (1.1.1) of the pinion, a first gear element (1.2) with a first toothing (1.2.5) arranged on its circumference, which is rigid and lies in a first plane perpendicular to the rotational axis, and a second gear element (1.3) with a second toothing (1.3.4) arranged on its circumference, which lies coaxially to the first toothing (1.2.5) in a second plane parallel to the first plane, wherein the pinion (1.1), the first (1.2) and the second gear element (1.3) are fixedly attached to one another and the second toothing (1.3.4) is arranged offset relative to the first toothing (1.2.5) by an angular range, thereby characterized in that said second toothing (1.3.4) is designed as a non-rigid toothing, wherein the second gear element (1.3) has a spring arm wheel (1.3.1) and elastically deformable spring arms (1.3.2), which are each attached to said spring arm wheel (1.3.1) at their inner end directed towards the axis of rotation and carry at least one tooth (1.3.3) of the second toothing (1.3.4) at their outer end directed towards the gear circumference, such that each tooth (1.3.3) or at least some of the teeth (1.3.3) of the second toothing (1.3.4) when acted upon by a wheel of the clockwork, or of the clock, which simultaneously meshes with the first (1.2.5) and second toothing (1.3.4) of the gear (1), independently of the other teeth (1.3.3) of the second toothing (1.3.4) carried by other spring arms (1.3.2). can be deflected springily.

2. Gear according to the preceding claim, characterized in that the first (1.2) and the second gear element (1.3) have substantially the same pitch circle radius and the said first toothing (1.2.5) and the said second toothing (1.3.4) have the same number of teeth.

3. Gear according to one of the preceding claims 1 to 2, characterized in that the second toothing (1.3.4) is arranged offset backwards by an angular range relative to the first toothing (1.2.5) against the direction of rotation of the gear (1), such that each tooth (1.3.3) or at least some of the teeth (1.3.3) of the second toothing (1.3.4) can be resiliently deflected when acted upon in the direction of rotation of the gear (1), or the second toothing (1.3.4) is arranged offset forwards by an angular range relative to the first toothing (1.2.5) in the direction of rotation of the gear (1), such that each tooth (1.3.3) or at least some of the teeth (1.3.3) of the second toothing (1.3.4) can be resiliently deflected when acted upon against the direction of rotation of the gear (1).

4. Gear according to one of the preceding claims 1 to 3, characterized in that said second toothing (1.3.4) has for each of its teeth (1.3.3) an elastically deformable spring arm (1.3.2), each elastically deformable spring arm (1.3.2) preferably being appreciably radially oriented.

5. Gear according to one of the preceding claims 1 to 3, characterized in that said second toothing (1.3.4) has at least one elastically deformable spring arm (1.3.2) for each part of adjacent teeth (1.3.3) located on a circular arc-shaped section of its circumference, wherein each of said circular arc-shaped sections preferably carries between 2 and 8 teeth (1.3.3) of the second toothing (1.3.4), particularly preferably between 2 and 6 teeth (1.3.3).

6. Gear according to one of the preceding claims, characterized in that the length (L) of each elastically deformable spring arm (1.3.2) is in the range of 15% to 75% of the radius (R) of said second gear element (1.3), preferably in the range of 25% to 50% of the radius (R) of the second gear element (1.3).

7. Gear according to one of the preceding claims, characterized in that the width (B F ) of each elastically deformable spring arm (1.3.2) is in the range of 5% to 80% of the width (B2) of the teeth (1.3.3) of said second toothing (1.3.4), preferably in the range of 10% to 40% of the width (B2) of the teeth (1.3.3) of the second toothing (1.3.4).

8. Gear according to one of the preceding claims, characterized in that the width (B2) of the teeth (1.3.3) of said second toothing (1.3.4) carried by the elastically deformable spring arms (1.3.2) is in the range from 20% to 80% of the width (Bi) of the teeth (1.2.4) of the first toothing (1.2.5), preferably in the range from 40% to 60% of the width (Bi) of the teeth (1.2.4) of the first toothing (1.2.5), wherein the teeth (1.3.3) of said second toothing (1.3.4) are particularly preferably designed as half teeth.

9. Gear according to one of the preceding claims, characterized in that the first - (1.2) and the second gear element (1.3) have positive alignment elements (1.2.2.1, 1.3.1.1) which ensure the fastening of the first - (1.2) and the second gear element (1.3) in at least one predefined relative position to each other, preferably in at least three predefined relative positions to one another, wherein the at least one predefined relative position ensures the centering of the first (1.2) and the second gear element (1.3) and each predefined relative position defines a predetermined angle by which the second toothing (1.3.4) is offset relative to the first toothing (1.2.5).

10. Gear according to the preceding claim, characterized in that the positive alignment elements (1.2.2.1, 1.3.1.1) are arranged by means of at least one pin mounted on the first gear element (1.2) or on the spring arm wheel (1.3.1) of the second gear element (1.3) (1.2.2.1), preferably by means of two pins (1.2.2.1), and for each pin (1.2.2.1) at least one, preferably three to seven, on the spring arm wheel (1.3.1) of the second gear element (1.3) or on the first gear element (1.2) arranged alignment opening (1.3.1.1).

11. Gear according to one of the preceding claims, characterized in that it has a fixed cover plate (1.4) for protecting the elastically deformable spring arms (1.3.2) of the second gear element (1.3) carrying the teeth of said non-rigid, second toothing (1.3.4), the cover plate (1.4) being mounted such that the second gear element (1.3) lies between the first gear element (1.2) and said cover plate (1.4).

12. Clockwork gear train for integration into a clockwork, or into a watch, which has at least two meshing gears, characterized in that at least one of the wheels of the gear train consists of a gear (1) according to one of the preceding claims.

13. Gear train according to the preceding claim 12, wherein the gear train comprises a large third wheel (2.2), a small third wheel (1.2, 1.3) driven by the large third wheel (2.2), a second wheel (3.2) driven by the small third wheel (1.2, 1.3) and a chronograph pinion (4.1) of a chronograph mechanism of the watch, also driven by the small third wheel (1.2, 1.3), characterized in that said small third wheel (1.2, 1.3) is part of a small third unit consisting of a gear wheel (1) according to one of the preceding claims 1 to 11.

14. Gear train according to the preceding claim 12, wherein the gear train comprises a gear wheel and an indicator drive driven by said gear wheel for driving a continuous display, wherein the indicator drive preferably serves to drive a counter, a small second display, a rattrapante mechanism, a day-night display and / or a moon phase display, characterized in that said gear wheel consists of a gear wheel (1) according to one of the preceding claims 1 to 11.

15. Clockwork movement for integration into a watch, in particular a chronograph clockwork movement for integration into a wristwatch, which comprises a power source, a gear train, an escapement and a regulating organ, characterized in that the gear train of the clockwork movement comprises a gear wheel (1) according to one of the preceding claims 1 to 11 or consists of a clockwork gear train according to one of the preceding claims 12 to 14.

16. Clockwork according to the preceding claim 15, which comprises at least one additional clock mechanism, in particular a chronograph mechanism, characterized in that the additional clock mechanism is driven by means of the gear (1) according to one of the preceding claims 1 to 11 or by means of the clockwork gear train according to one of the preceding claims 12 to 14.

17. Clock, in particular a wristwatch with a chronograph clockwork, characterized in that the clock has a gear (1) according to one of the preceding claims 1 to 11, a clockwork gear train according to one of the preceding claims 12 to 14 or a clockwork according to one of the preceding claims 15 to 16.

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