NL2033700B1

NL2033700B1 - Energy storage system for a mechanical watch

Info

Publication number: NL2033700B1
Application number: NL2033700A
Authority: NL
Inventors: Pieter Lustig Maarten; Frances Louise Gerlach Robyn; Jessica Giuffre Eola; Michiel Helwig Roemer
Original assignee: Rolex Sa
Priority date: 2022-12-09
Filing date: 2022-12-09
Publication date: 2024-06-14
Also published as: WO2024121368A1; EP4630885A1; CN120225964A

Abstract

A. energy storage system. (1) for a mechanical watch, said energy storage system comprising a spiral spring (2) for 5 storing mechanical energy to drive the mechanical watch, which spiral spring' (2) is arranged. to occupy a space or volume within the energy storage system (1) which is substantially independent of the amount of energy stored after tensioning or compression of the spiral spring (2), wherein the spring (2) 10 comprises a series of Hmtually connected repeating elements (4), wherein each two neighbouring elements (4) are connected to each other by a shape—invariable connecting portion (5), and. that the mutually connected. repeating' elements (4) are arranged to receive the energy stored in the spiral spring (2) 15 in independent parts distributed over said mutually connected elements (4) that are loaded by the tensioning or compression of the spiral spring (2). [Fig. 2]

Description

Energy storage system for a mechanical watch

The invention relates to an energy storage system for a mechanical watch, said energy storage system comprising a spiral spring for storing mechanical energy to drive the mechanical watch, which spiral spring is arranged to occupy a space or volume within the energy storage system which is substantially independent of the amount of energy stored after tensioning or compression of the spiral spring.

EP 2 705 271 B1/US 8,950,552 discloses a barrel, which is intended to provide a more compact spring at rest, and whose torque is less dependent on the degree of winding of the spring. To that end the just mentioned publications teach to apply energy accumulation curves integral with the spring, which curves are of substantially rectangular cross-section forming alternations with respect to a spiral trajectory over at least a part of the coils of the spring.

The object of the invention is to improve the energy density of the spiral spring as applied in the energy storage system of the invention, for which purpose the invention applies the features of one or more of the appended claims.

According to a first aspect of the invention the spring comprises a series of mutually connected repeating elements, wherein each two neighbouring elements are connected to each other by a shape-invariable connecting portion, and that the mutually connected repeating elements are arranged to receive the energy stored in the spiral spring in independent parts distributed over said mutually connected elements that are loaded by the tensioning or compression of the spiral spring.

By the application of the shape invariable connecting portions the energy is forced to be stored and released from the respective repeating elements which form so-called building blocks of the spring of the energy storage system of the invention.

The series of building blocks for the construction of the spring of the energy storage system of the invention is preferably arranged such that the spring comprises a beginning portion, a middle portion, and an end portion, and that the series of repeating elements constitute at least the middle portion. The energy exchange portion of the spring is then concentrated indeed in this middle portion.

In order to be able to store and release energy from a spring without materially changing the spring's volume, it is preferred that the repeating elements are each provided with the property that a tension or compression applied to an element of the spring resulting in an elongation or retraction of such element in a first direction converts into a simultaneous retraction or elongation of said element in a second direction. Most preferred is that the second direction is essentially orthogonal to the first direction.

A preferred embodiment is arranged such that during tensioning or compression applied to an individual element of the spring, a volume occupied by such individual element remains essentially the same.

Suitably each repeating element or each combination of two subsequent repeating elements comprises a predominantly S- shaped part. It is further preferred that the series of repeating elements are configured into said spiral that is housed in the energy storage system.

A noteworthy feature of the energy storage system of the invention which further differentiates the energy storage system from the prior art, is that the spiral of the series of

- 3 = repeating elements is free from alternations so as to maximize the space or volume that the spring occupies in the energy storage system and to optimize the energy density that is storable in the spring.

In designing the energy storage system of the invention better performance and reliability may be achieved by arranging that the repeating elements are similarly shaped.

Also, better performance and reliability may be achieved by arranging that the repeating elements are essentially identical in shape. It may in particular be beneficial that the repeating elements are provided with the same dimensions.

To promote the working efficiency of the energy storage system of the invention it is desirable that the repeating elements comprise flexible structures.

The object of the invention can be effectively achieved by arranging that the repeating elements are placed in a tail to head sequence with respect to each other.

In one embodiment the repeating elements have a top and a toe and are provided with a varying thickness from top to toe.

It may further be desirable that the repeating elements have a varying curvature from top to toe.

It is particularly preferable that the repeating elements are engaged by a guiding system separating adjacent turns of the spiral so as to avoid jamming of said adjacent turns.

Advantageously the repeating elements are equipped with slits along at least part of their length to optimize deformation of the repeating elements and/or the distribution of stresses along the repeating elements.

The energy storage system can be used for storing and supplying energy to various mechanisms in the watch, such as a barrel used to drive a finishing gear and to maintain the oscillations of an oscillator, or for a barrel driving an additional or complication mechanism such as a repeater or an alarm, or for driving a specific mechanism such as a date or month or year or moon phase indication (for enabling an instantaneous multiple date jump in a perpetual calendar, for example), or even for the balance spring of a balance-spring oscillator. The system could also drive a shaft or a rake in partial rotation, or perform a linear displacement.

The accompanying drawing, which is incorporated into and forms a part of the specification, illustrates one or more embodiments of the present invention and, together with the description, serves to explain the principles of the invention. The drawing is only for the purpose of illustrating one or more embodiments of the invention and is not to be construed as limiting the invention.

In the drawing: - figure 1 shows a barrel with a spring of the invention in several stages of loading; - figure 2 shows an oblique top view at a barrel with a spring according to the invention; - figure 3 shows a detail view at a series of connected repeating elements forming a part of the spring of figure 2; — figure 4 shows a series of connected repeating elements as shown in figure 3 bounded by a guiding system to avoid

Jamming; and - figure 5 shows an alternative embodiment of a barrel with a spring according to the invention.

Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.

Figure 1 shows the general concept of a barrel 1 for a mechanical watch or timepiece, in several stages of loading of its spiral spring 2. On the left the barrel 1 is completely unloaded, whereas on the right the barrel 1 is partially loaded.

Figure 2 shows an oblique view from above at a first embodiment of a spring 2 mounted in a barrel 1, which shows that the spring 2 is connected to an axle 3 in the center of the barrel 1,

A second embodiment of a spring 2 mounted in a barrel 1 is shown in figure 5.

As is common in the art the spiral spring 2 of each embodiment is used for storing mechanical energy to drive the mechanical watch. As can be seen from the several stages of loading of the barrel spring 2 depicted in figure 1, the spiral spring 2 is arranged to occupy a space or volume within the barrel 1 which is substantially independent of the amount of energy stored after tensioning or compression of the spiral spring 2.

In Figure 1, the elements are shown as being deformed sequentially, meaning that the elements are designed such that one element can only be deformed if the previous element has been fully deformed. Alternatively, the elements can be deformed in a parallel manner, i.e. the deformation is then distributed more or less evenly over the individual elements.

In the detailed view of figure 3 that relates to the first embodiment of figure 2 it is shown that the spring 2 comprises a series of mutually connected repeating elements 4, wherein each two neighbouring elements 4 are connected to each other by a shape-invariable connecting portion 5. The mutually connected repeating elements 4 are arranged to receive the energy stored in the spiral spring 2 in independent parts, said parts being the mutually connected elements 4 that are loaded by the tensioning or compression of the spiral spring 2. This likewise applies to the embodiment of figure 5, which has an alternative arrangement of the mutually connected elements 4 and the shape-invariable connecting portion 5.

The series of repeating elements 4 of each embodiment are configured into the spiral spring 2 that is housed in the barrel 1. As will be clear from the drawing of fig. 2 and fig. 5, the spiral spring 2 comprising the series of repeating elements 4 is free from alternations so as to maximize the space or volume that the spring 2 occupies in the barrel 1 and to optimize the energy density that is storable in the spring 2. One can further identify that the spring 2 comprises a beginning portion, a middle portion, and an end portion, and that the series of repeating elements 4 constitute at least the middle portion. The beginning portion and the end portion are connected to the central axle 3 of the barrel 1 as well as to the barrel at a location 6 near to the barrel’s outer circumference.

The structure of the series of repeating elements 4 applied in the embodiments of figure 2 and figure 5, attributes the property to these repeating elements 4 that a tension or compression applied to an element 4 of the spring which results in an elongation or retraction of such element in a first direction, will convert into a simultaneous retraction or elongation of said element in a second direction. This is reflected in figure 1 which depicts several stages of loading of the spiral spring 2. It will be recognized that the second direction is essentially orthogonal to the first direction.

A noteworthy property of the spring 2 as applied in the invention is that during tensioning or compression which is applied to an element 4 of the spring 2, a volume occupied by such element 4 remains essentially the same. As is clearly shown in the embodiment of figure 2, each combination of two subsequent repeating elements 4 comprises a predominantly S- shaped part. It is also possible however that each single repeating element 4 comprises a predominantly S-shaped part as depicted in figure 5, with S-shaped parts arranged in a symmetrically inverted manner.

It is further clear from figure 2 and figure 5 that the repeating elements 4 are similarly shaped, and even further that the repeating elements 4 may be essentially identical in shape. It is further noted that the repeating elements 4 can be provided with the same dimensions. Alternatively, the dimensions of the repeating elements could vary along the spiral, for example be arranged to have a rigidity of the repeating elements that decreases from one end to the other end, so that for example the exterior elements are less rigid than the interior elements, to promote uniform or comparable deformation of the various repeating elements during tensioning or compression.

It is further possible to combine different types of repeating elements, for example to combine elements such as those of figure 2 and figure 5 in the same spring.

Desirably the repeating elements 4 comprise flexible structures. Further figure 2 and figure 5 depict that the repeating elements 4 are placed in a tail to head sequence with respect to each other. It can further be noted that the repeating elements 4 may have a top 4' and a toe 47’ and are provided with a varying thickness from top 4’ to toe 4’ as is most clearly shown in figure 3. On an individual scale the repeating elements 4 may have a varying curvature from top 4’ to toe 477.

In some embodiments it is beneficial that the repeating elements 4 are engaged by a guiding system 7 separating adjacent turns of the spiral of the repeating elements 4 so as to avoid Jamming of said adjacent turns of the spiral. The guiding system 7 is depicted in figure 4 being provided on both sides of a single turn of the spiral of repeating elements 4. Alternatively, the guiding system could consist of a thin strip inserted between the adjacent turns of the spiral spring.

As shown on figure 5, the repeating elements can consist of various solid flexible parts. Alternatively, as shown on figure 3, the repeating elements can have slits 8 along at least part of their length to optimize deformation of the repeating elements and/or the distribution of stresses along the repeating elements, notably during tensioning or compression.

The energy storage system can store energy by tensioning the spring in winding, for example by rotating the axle 3 in figure 2 in the counter clockwise direction, or by moving the end portion of the spring or the outer circumference of the barrel in the clockwise direction, and supply energy through rotation in the other direction. Alternatively, the spring of the energy storage system can store energy by being compressed. A preload can also be applied to the spring and/or system.

Figure 2 shows a spring formed of one layer of material. To increase the amount of energy storable in the system, the height of the spring can be increased. Alternatively, several identical or comparable springs can be stacked and assembled

- Gg - at their respective ends to form a spring extending over several different layers. Such an assembly can be provided by stacking and assembling the springs in series (meaning that the input of a spring is connected to the output of the preceding spring), or in parallel (meaning that part or all the inputs, respectively part or all the outputs, of the springs are connected together.

As material for the spring, a material that can be formed by micromachining and/or by etching and/or by additive manufacturing can be suitable. In particular, materials such as Silicon or Silicon Carbide, optionally with an additional coating (for example Silicon Oxide), can be especially suitable. A combination of several materials and/or fabrication techniques can also be used.

Embodiments of the present invention can include every combination of features that are disclosed herein independently from each other. Although the invention has been discussed in the foregoing with reference to an exemplary embodiment of the invention, the invention is not restricted to this particular embodiment which can be varied in many ways without departing from the invention. The discussed exemplary embodiment shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary the embodiment is merely intended to explain the wording of the appended claims without intent to limit the claims to this exemplary embodiment. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using this exemplary embodiment.

Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference. Unless specifically stated as being “essential” above, none of the various components or the interrelationship thereof are essential to the operation of the invention. Rather, desirable results can be achieved by substituting various components and/or reconfiguration of their relationships with one another.

Aspects of the invention are itemized in the following section. 1. An energy storage system (1) for a mechanical watch, said energy storage system comprising a spiral spring (2) for storing mechanical energy to drive the mechanical watch, which spiral spring (2) is arranged to occupy a space or volume within the energy storage system (1) which is substantially independent of the amount of energy stored after tensioning or compression of the spiral spring (2), characterized in that the spring (2) comprises a series of mutually connected repeating elements (4), wherein each two neighbouring elements (4) are connected to each other by a shape-invariable connecting portion (5), and that the mutually connected repeating elements (4) are arranged to receive the energy stored in the spiral spring (2) in independent parts distributed over said mutually connected elements (4) that are loaded by the tensioning or compression of the spiral spring (2). 2. The energy storage system of claim 1, characterized in that the spring comprises a beginning portion, a middle portion, and an end portion, and that the series of repeating elements (4) constitute at least the middle portion. 3. The energy storage system of claim 1 or 2, characterized in that the repeating elements (4) are each provided with the property that a tension or compression applied to an element (4) of the spring (2) resulting in an elongation or retraction of such element (4) in a first direction converts into a simultaneous retraction or elongation of said element (4) in a second direction.

4. The energy storage system of claim 3, characterized in that the second direction is essentially orthogonal to the first direction.

5. The energy storage system of any one of claims 1-

4, characterized in that during tensioning or compression applied to an element (4) of the spring (2), a volume occupied by such element (4) remains essentially the same.

6. The energy storage system of any one of claims 1- 5, characterized in that each repeating element (4) or each combination of two subsequent repeating elements (4) comprises a predominantly S-shaped part.

7. The energy storage system of any one of claims 1- 6, characterized in that the series of repeating elements (4) are configured into said spiral that is housed in the energy storage system (1).

8. The energy storage system of claim 7, characterized in that the spiral of the series of repeating elements (4) is free from alternations so as to maximize the space or volume that the spring (2) occupies in the energy storage system (1) and to optimize the energy density that is storable in the spring (2).

9. The energy storage system of any one of claims 1- 8, characterized in that the repeating elements (4) are similarly shaped.

10. The energy storage system of any one of claims 1- 9, characterized in that the repeating elements (4) are essentially identical in shape.

11. The energy storage system of any one of claims 1- 10, characterized in that the repeating elements (4) are provided with the same dimensions.

12. The energy storage system of any one of claims 1- 11, characterized in that the repeating elements (4) comprise flexible structures. 13. The energy storage system of any one of claims 1- 12, characterized in that the repeating elements (4) are placed in a tail to head sequence with respect to each other. 14. The energy storage system of any one of claims 1- 13, characterized in that the repeating elements (4) have a top (47) and a toe (4’’) and are provided with a varying thickness from top to toe. 15. The energy storage system of any one of claims 1- 13, characterized in that the repeating elements (4) have a varying curvature from top (4') to toe (477). 16. The energy storage system of any one of claims 1- 15, characterized in that the repeating elements (4) are engaged by a guiding system (7) separating adjacent turns of the spiral so as to avoid jamming of said adjacent turns. 17. The energy storage system of any one of claims 1- 16, characterized in that the repeating elements (4) are equipped with slits (8) along at least part of their length to optimize deformation of the repeating elements (4) and/or the distribution of stresses along the repeating elements (4).

Claims

CONCLUSIONS

1. An energy storage system (1) for a mechanical watch, the energy storage system comprising a coil spring (2) for storing mechanical energy to drive the mechanical watch, the coil spring (2) being adapted to occupy a space or volume in the energy storage system (1) which is substantially independent of the amount of energy stored upon tensioning or compressing the coil spring (2), characterised in that the spring (2) comprises a series of interconnected repeating elements (4), each two adjacent elements (4) being interconnected by a form-retaining connecting portion (5), and in that the interconnected repeating elements (4) are arranged to receive the stored energy in the coil spring (2) in independent portions distributed over said interconnected elements (4) which are loaded upon tensioning or compressing the coil spring (2).

2. An energy storage system according to claim 1, characterized in that the spring comprises a starting portion, a middle portion and an end portion, and that the series of repeating elements (4) forms at least the middle portion.

3. Energy storage system according to claim 1 or 2, characterised in that the repeating elements (4) each have the property that a tension or compression applied to an element (4) of the spring (2) resulting in an extension or retraction of such element (4) in a first direction is converted into a simultaneous retraction or extension of said element (4) in a second direction.

4. An energy storage system according to claim 3, characterized in that the second direction is substantially perpendicular to the first direction.

5. Energy storage system according to any one of claims 1 to 4, characterised in that during tensioning or compression of an element (4) of the spring (2), a volume occupied by that element (4) remains substantially the same.

6. Energy storage system according to any one of claims 1 to 5, characterised in that each repeating element (4) or each combination of two consecutive repeating elements (4) comprises a predominantly S-shaped part.

7. Energy storage system according to any one of claims 1 to 6, characterised in that the series of repeating elements (4) is formed into the spiral housed in the energy storage system (1).

8. An energy storage system according to claim 7, characterised in that the spiral of the series of repeating elements (4) is free of alternations in order to maximise the space or volume occupied by the spring (2) in the energy storage system (1) and to optimise the energy density that can be stored in the spring (2).

9. Energy storage system according to any one of claims 1 to 8, characterised in that the repeating elements (4) are of the same shape.

10. Energy storage system according to any one of claims 1 to 9, characterised in that the repeating elements (4) are essentially identical in shape.

11. Energy storage system according to any one of claims 1 to 10, characterised in that the repeating elements (4) have the same dimensions.

12. Energy storage system according to any one of claims 1 to 11, characterised in that the repeating elements (4) comprise flexible structures.

13. Energy storage system according to any one of claims 1 to 12, characterised in that the repeating elements (4) are arranged in a tail-to-head arrangement relative to each other.

14. Energy storage system according to any one of claims 1 to 13, characterised in that the repeating elements (4) have a top (4') and a toe (4'') and have a varying thickness from top to toe.

15. Energy storage system according to any one of claims 1 to 13, characterised in that the repeating elements (4) have a varying curvature from top (4') to bottom (4'').

Energy storage system according to any one of claims 1 to 15, characterised in that the repeating elements (4) are engaged by a guide system (7) which separates adjacent turns of the spiral to prevent jamming of said adjacent turns,

17. Energy storage system according to any one of claims 1 to 16, characterised in that the repeating elements (4) are provided with slots (8) over at least part of their length to optimise deformation of the repeating elements (4) and/or to optimise the stress distribution along the repeating elements (4).