EP4630885A1 - Energy storage system for a mechanical watch - Google Patents

Abstract

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 spring (2) comprises a series of mutually connected repeating elements (4), wherein each two neighbouring elements (4) are connected to each other by a connecting portion (5), and that the mutually connected repeating elements (4) are arranged to receive the energy stored in the spiral spring (2), wherein 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.

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 spring comprises a series of mutually connected repeating elements , wherein each two neighbouring elements are connected to each other by a connecting portion, and that the mutually connected repeating elements are arranged to receive the energy stored in the spiral spring .

EP 2 705 271 Bl /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 j ust 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 traj ectory over at least a part of the coils of the spring .

The obj ect 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 repeating elements are engaged by a guiding system separating adj acent turns of the spiral so as to avoid j amming of said adj acent turns .

According to a second aspect which can be applied independent or in combination with the first aspect of the invention, the repeating elements are equipped with s lits along at least part of their length to optimi ze deformation of the repeating elements and/or the distribution of stresses along the repeating elements .

According to a third aspect of the invention, which can be applied independent or in combination with the first aspect and/or the second aspect of the invention, each repeating element or each combination of two subsequent repeating elements comprises a predominantly S-shaped or sinusoid-shaped part , wherein the repeating elements have a top or tops represented by extremes of the S-shape or sinusoid-shaped , and a toe or toes at points of inflection between said tops , wherein the repeating elements are provided with a varying thickness from top to toe .

Preferably 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, wherein the second direction is essentially orthogonal to the first direction so as to arrange that during tensioning or compression applied to an element of the spring, a volume occupied by the spring remains essentially the same .

A noteworthy feature of the energy storage system of the invention which further di f ferentiates the energy storage system from the prior art , is that the spiral of the series of repeating elements is free from alternations as known from EP 2 705 271 Bl /US 8 , 950 , 552 , so as to maximi ze the space or volume that the spring occupies in the energy storage system and to optimi ze the energy density that is storable in the spring .

In des igning 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 reliabi lity 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 e f ficiency of the energy storage system of the invention it is desirable that the repeating elements comprise flexible structures .

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

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 speci fic mechanism such as a date or month or year or moon phase indication ( for enabling an instantaneous multiple date j ump in a perpetual calendar, for example ) , or even for the balance spring of a balance-spring oscillator . The system could al so 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 speci fication, 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 di f ferent embodiments of a guiding system to avoid j amming; 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 o f 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 i f 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 i s shown that the spring 2 compri ses a series of mutually connected repeating elements 4 , wherein each two neighbouring elements 4 are connected to each other by a connecting portion 5 . The mutually connected repeating elements 4 are arranged to receive the energy stored in the spiral spring 2 . This likewise applies to the embodiment of figure 5 , which has an alternative arrangement o f the mutually connected elements 4 and the 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 wil l be clear from the drawing o f f ig . 2 and f ig . 5 , the spiral spring 2 comprising the series of repeating elements 4 is free from alternations so as to maximi ze the space or volume that the spring 2 occupies in the barrel 1 and to optimi ze the energy density that is storable in the spring 2 . One can further identi fy 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 appl ied 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 o f such element in a f irst 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 recogni zed that the second direction is essentially orthogonal to the first direction .

During tensioning or compression applied to an element 4 of the spring 2 , the volume occupied by the spring 2 remains preferably es sential ly 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 or sinusoid-shaped part . It is also possible however that each single repeating element 4 comprises a predominantly S-shaped or sinusoid-shaped part as depicted in f igure 5 , wherein the 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 dimens ions 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 uni form or comparable deformation of the various repeating elements during tensioning or compression .

It is further possible to combine di f ferent 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 tai l to head sequence with respect to each other . It can further be noted that the repeating elements 4 comprise a predominantly S-shaped or sinusoid-shaped part , and that the repeating elements 4 have a top 4 ' or tops represented by extremes of the S-shape or sinusoid-shaped , and a toe 4 ' ’ or toes at points of inflection between said tops , and are provided with a varying thickness from top to toe , 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 4 ' ' .

The repeating elements 4 are engaged by a guiding system 7 separating adj acent turns of the spiral of the repeating elements 4 so as to avoid j amming of said adj acent turns of the spiral . The guiding system 7 is depicted in figure 4 and is provided on both sides of a single turn of the spiral of repeating elements 4 . Alternatively, the guiding system could consist o f a thin strip inserted between the adj acent turns of the spiral spring . Alternatively, the guiding system could consist of connecting portions 5 that are located at the tops of the repeating elements 4 , such as in figure 5 . 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 optimi ze 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 o f 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 compres sed . 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 at their respective ends to form a spring extending over several di f ferent 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 modi fications 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 modi fications and equivalents . The entire disclosures of all references , applications , patents , and publications cited above are hereby incorporated by reference . Unless speci fically stated as being "essential" above , none o f 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 .

Claims

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 spring (2) comprises a series of mutually connected repeating elements (4) , wherein each two neighbouring elements (4) are connected to each other by a connecting portion (5) , and that the mutually connected repeating elements (4) are arranged to receive the energy stored in the spiral spring (2) , 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.

2 . The energy storage system according to the preamble of claim 1 or according to claim 1, 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) .

3. The energy storage system according to the preamble of claim 1, or according to any one of claims 1-2, characterized in that each repeating element (4) or each combination of two subsequent repeating elements (4) comprises a predominantly S- shaped or sinusoid-shaped part, and that the repeating elements (4) have a top (4' ) or tops represented by extremes of the S- shape or sinusoid-shaped , and a toe (4^{, f} ) or toes at points of inflection between said tops, wherein the repeating elements (4) are provided with a varying thickness from top to toe.

4. The energy storage system according to any one of claims 1 - 3, 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, wherein the second direction is essentially orthogonal to the first direction so as to arrange that during tensioning or compression applied to an element (4) of the spring (2) , a volume occupied by the spring (2) remains essentially the same.

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

4, 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) .

6. The energy storage system of any one of claims 1-5, characterized in that the repeating elements (4) are placed in a tail to head sequence with respect to each other.