Patent Application
20190018367
This application claims priority from European Patent Application No. 17180736.5 filed on Jul. 11, 2017, the entire disclosure of which is hereby incorporated herein by reference.
The present invention concerns an oscillating winding weight for a timepiece with an automatic movement. More particularly, the invention concerns a winding weight of this type intended to be fitted to a wristwatch comprising a transparent back cover, said weight being arranged on the side of the back cover of the case and allowing permanent observation of the entire movement.
Wristwatches having cases with transparent back covers to allow their movement to be observed are already known. However, when these watches comprise a movement with an automatic winding mechanism, observation of the movement is always curtailed by the presence of the oscillating winding weight which, even when openworked, as is the case in so-called ‘skeleton’ watches, prevents comfortable observation of the movement.
To overcome this problem, EP Patent No. 0957414 proposed an oscillating winding weight comprising a heavy portion secured to a connecting element to connect said heavy portion to an arbor integral with a movement, said connecting element being made of a transparent or translucent material. Such an oscillating winding weight allows the movement to which it is fitted to be observed with no visible obstacles. However, certain elements of the movement, which appear through the oscillating winding weight and through the transparent back cover of the watch, have their usual metallic appearance while the rest of the watch may be very colourful. Although colour can be added to some fixed elements of the movement frame without difficulty, the same is not true of the moving parts of the gear train, such as parts of the going train, of the escapement or of the oscillator. It is complex to add colour to these moving parts. Indeed, the functionality of these parts, which require high precision and the least possible friction in order to operate properly, could not be guaranteed following application of a coloured film, for example.
It is an object of the present invention to overcome the drawbacks of the aforementioned prior art by proposing an oscillating winding weight for a timepiece that allows the parts of the movement to which it is fitted to be given a colour without harming the functionality of such parts.
To this end, the invention concerns an oscillating winding weight for a timepiece movement comprising a heavy portion fixed to a connecting element connecting said heavy portion to an arbor fixed to a movement, said weight being intended to be rotatably mounted on said arbor, said connecting element being made of a transparent or translucent material.
According to the invention, said connecting element comprises at least one coloured filter.
As a result of this novel winding weight structure, it is possible to make the whole of the timepiece movement to which it is fitted permanently visible, and to give the visible parts of the movement a coloured appearance, in a different colour from their real colour, which gives the timepiece an improved aesthetic appearance, without harming the functionality of such parts.
Said coloured filter can occupy at least part of the surface of the connecting element.
According to a particularly preferred embodiment of the invention, the coloured filter occupies the entire surface of the connecting element and is preferably formed by a mass-coloured component of the transparent or translucent material.
According to another aspect, the invention also concerns a timepiece comprising a case formed of a case middle closed by a crystal and an at least partially transparent back cover and inside which is housed a timepiece movement with an automatic winding mechanism, said movement being fitted with an oscillating winding weight as defined above.
Other details of the invention will appear more clearly upon reading the following description, made with reference to the annexed drawings, in which:
Winding weight 1 comprises a heavy portion 2 fixed to a connecting element 4 intended to connect the heavy portion to an arbor (not represented) integral with a timepiece movement, weight 1 being intended to be rotatably mounted on said arbor. To this end, the connecting element comprises at its centre an opening 6, into which is driven a ring 8, forming the hub of weight 1.
In this variant, connecting element 4 is formed of a full disc made of a transparent material such as sapphire, which allows the movement to be observed through weight 1. It is recalled that the use of sapphire in a winding weight as connecting element between the heavy portion and the movement goes against the preconceived ideas of those skilled in the art who, when designing a winding weight, always tend to use materials having high resistance, i.e. good capacity to absorb the shocks to which the weight is subjected during its rotation. It is evident that any other transparent or translucent, synthetic or natural material can be used. For example, a polycarbonate suitable for this application can be used. In all cases, the material will at least have to allow light to pass through in order to distinguish the shapes of the elements situated behind it.
Heavy portion 2 comprises a ring 10 which comprises, on an arc of a circle of approximately 180°, an unbalance 12, which is formed by an overthickness of said ring 10. In the illustrated example, ring 10 and unbalance 12 are made in one piece. Preferably, heavy portion 2 is made of a high density metal, for example, a tungsten alloy. However, it is evident that, according to a variant, unbalance 12 can be secured to ring 10 by any conventional securing means, such as screwing, bonding, crimping, soldering or suchlike. In that case, ring 10 can be made of a material that is easy to machine, such as steel, and unbalance 12 of a tungsten alloy. In the example shown, ring 10 comprises a rabbet 14 in which disc 4 is engaged and bonded. However, it is evident that according to a variant, this disc 4 can be fixed in rabbet 14 of ring 10 by any other conventional securing means, such screwing, riveting or suchlike. Preferably, ring 10 has a decoration on its external surface, i.e. visible from the back cover of the watch. This decoration preferably occupies the whole of the external visible surface of the ring.
According to the invention, connecting element 4 comprises at least one coloured filter 30, which occupies the whole of the surface of connecting element 4.
According to another variant of the invention, the coloured filter may occupy only part of the surface of the connecting element. For example, the coloured filter may be in the form of a strip, a continuous or discontinuous ring, arranged on the connecting element substantially level with the visible parts of the movement which one wishes to give a coloured appearance, at least temporarily, according to the rotational motion of the oscillating winding weight.
Preferably, said coloured filter 30 can be formed by a coloured component within the transparent or translucent material. For example, a dye, a pigment or a mixture of dyes and pigments, diffused through the transparent or translucent material, will be used. This embodiment will be particularly preferred when the coloured filter occupies the whole of the surface of the connecting element.
When the transparent or translucent material is polycarbonate, the dyed-in-the-mass connecting element 4 may, for example, be obtained from a compound comprising polycarbonate, a pigment or a mixture of pigments and a dispersing agent. This compound is then injected to obtain connecting element 4. It is also possible to use a pigment directly in liquid form. Any pigment compatible for dying in the mass the transparent or translucent material can be used.
According to another embodiment, the coloured filter can be formed by a transparent or translucent coloured film deposited on at least one part of the surface of connecting element 4. This film may be a varnish or an ink. It can be deposited on the internal surface (movement side) or external surface (back cover side) of connecting element 4. This embodiment can be implemented to form a coloured filter that occupies all or part of the surface of the connecting element.
Further, in a particularly advantageous manner, at least one element of the movement which is at least partially visible from the back of the movement and can be at least partially seen through the coloured filter, has a neutral colour, for example grey, with a matt effect. This neutral colour is chosen so as not to reduce, or to reduce as little as possible, the effect of the coloured filter. Thus, connecting element 4 acts as a coloured filter and gives the illusion that the elements visible from the back of the movement are coloured, with a different colour from their real colour. The invention thus allows the elements visible from the back of the movement to be given a different colour from their natural colour, without harming their functionality. Depending on whether the coloured filter occupies all or part of the surface of the connecting element, the effect of the coloured appearance given to the elements visible from the back of the movement is permanent or temporary but repeated according to the rotational motion of the oscillating winding weight.
Unlike the embodiment shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 17180736.5 | Jul 2017 | EP | regional |
