EP3226236B1 - Improvement for accordion - Google Patents

Description

Technical field of the invention

The present invention relates to an improvement for accordion.

State of the art

There are different types of accordions and neighboring instruments by design such as bandoneons and concertinas. All have in common to include on the one hand a bellows to suck and repress air to oscillate sound waves and two keyboards each activated by a hand of the instrumentalist. Each of the two keyboards is implanted on a rigid support in the form of a hollow box connected to one of the two ends of the bellows.
The differences between accordions, concertinas and bandoneons are numerous and concern in particular their bellows as well as the composition and arrangement of their respective keyboards.

The bandoneons and concertinas have bellows of small transverse dimensions and hexagonal or octagonal external shapes, therefore of regular polygonal shapes, all virtual vertices of which are writable in a circle. This shape which tends to approach a circle provides great flexibility to the bellows which allows almost complete freedom of movement in all directions of one hand relative to the other in the opening and closing maneuvers of the bellows but in return it requires the player to play in a sitting position. Indeed, the reduced width and height of these instruments require a large unfolding length of said bellows to be able to have a reserve of air that is sufficient to play. These reduced transverse dimensions associated with a large length of unfolding of the bellows result in a lack of holding said bellows when it is in the unfolded position which therefore requires that it can rest on the legs of the seated player.

In contrast to bandoneons and concertinas, the accordion bellows are of rectangular shape that is taller than they are wide, which gives it sufficient strength to prevent it from collapsing when it is deployed, which allows the accordionist to play standing or moving while playing. These large dimensions of the bellows associated with its rectangular shape, however, have the double disadvantage of being very cumbersome and greatly limit the visual field of the accordionist forward and downward which is very disadvantageous both when must move while playing only when he plays on stage without being able to see the spectators of the first ranks or when he plays sitting while reading a score placed on a desk in front of him that he must have in position sufficiently high to be able to read it the bottom and the desk then partly hides the player in the eyes of his listeners (see for example, the patent number GB 787.809 ).

Moreover, at the level of ergonomics, the vertical arrangement of the keyboard operated by the hand playing the melody, so the right hand for a right-handed accordion, requires the corresponding arm to be constantly folded at a very closed angle what is translated by problems of blood circulation and troublesome cramps of the forearm for the accordionist. The left arm must support the weight of the accompanying keyboard and the box on which it is mounted and the weight of the entire unfolded part of the bellows and all this is again a cause of muscle fatigue important to the arm left especially for small accordionists or accordionists who lack muscular strength and sufficient physical condition.

Finally the current bellows are expensive to achieve because they require many manual interventions and they are also made of materials that fear moisture and raindrops and this therefore makes them limited use outdoors and does not allow not otherwise to wash them to maintain them in a perfect state of cleanliness

Objects of the invention

The arrangements described in this invention obviate the aforementioned drawbacks by proposing an instrument according to claim 1, whose shapes and optimized dimensions of the bellows allow to have a sufficient volume of air to play while freeing up the visual field of the accordionist that he is playing standing or sitting.

Another object of the invention is to provide an instrument with more ergonomic shapes for greater playing comfort both standing and sitting.

Another object of the invention is to lighten the instrument as much as possible and in particular to reduce as much as possible the weight supported by the hand, the arm and the shoulder operating the bellows and the accompanying keyboard.

Another object of the invention is also to improve the spatial acoustic projection performance of the instrument.

Another object of the invention is to provide a manufacturing method largely industrializable so as to reduce its cost.

Yet another object of the invention is to provide an instrument that does not fear ambient humidity and can be easily cleaned with a wet sponge.

Beforehand, to facilitate the description and understanding of this document, we first agree that the substantially vertical face of the accordion and the corresponding face, also substantially vertical, of the bellows bearing against the chest of the player will be designated under the rear face of the accordion and the rear face of the bellows while the face, substantially vertical, opposite, visible by the spectators facing the accordionist will be referred to as the front face of the accordion and face before the bellows. Whatever the position in which the accordion is represented, the right-hand side of the instrument will be the one on the right-hand side of the instrumentalist while the left-hand side of the instrument will be the one located on the left. side of the accordionist's left hand.

We also agree that the reference planes are defined with reference to an accordion whose bellows are completely folded and which rests in its vertical position on a horizontal support by its smallest dimension so that its keyboards are located laterally on the left and right. Another of the bellows and their rows of buttons extend in the vertical direction. On these bases the plane called the median vertical longitudinal plane (V V ') is the plane passing substantially mid-thickness of the instrument and this plane is thus disposed substantially perpendicular to the two planes containing for one the peripheral contour of the end of the bellows located on the side of the right hand of the player and for the second the peripheral contour of the end of the bellows located on the side of the left hand of the player. On these same bases the median horizontal longitudinal plane (H H ') is the plane passing substantially halfway up the instrument while being disposed substantially parallel to the horizontal support on which the accordion is placed and this plane is thus also arranged substantially perpendicular to the two end planes of the bellows as described above. Finally the median vertical transverse plane (ZZ ') is the vertical plane passing substantially mid-length of the bellows while being moreover arranged parallel to the end faces of said bellows when it is completely folded.

According to a first embodiment, the bellows of the accordion according to the invention consists of a juxtaposition of inner folds and outer folds constituting closed frames whose outer corners are rounded in a radius or are chamfered. The closed peripheral contours of at least some of the outer plies are of polygonal shape comprising at least three sides and at least one interior corner of said polygon, ie at least one vertex angle of said polygon, does not have the same value as the another angle or the 2, 3, or 4 other angles depending on whether the polygon has respectively 3, 4, 5 or 6 sides while at least one side of said polygon is of a length different from that of the other sides of the polygon.

According to other embodiments, the closed peripheral contours of at least some of the outer plies are of polygonal shape comprising at least three sides and at least two interior angles of said polygon, ie at least two corners at the top of said polygon, n ' have the same value as the other angle or the 2, 3, 4 or 5 other angles depending on whether the polygon has respectively 3, 4, 5, 6 or 7 sides while at least two sides said polygon are of different lengths than the other sides of the polygon.

According to another characteristic, the closed peripheral periphery of at least some of the outer folds constituting the bellows as described above constitutes a polygon of irregular shape in that the sides of said polygon are not all equal to each other nor are they all equal to each other. two.
According to another characteristic, the closed circumferential periphery of at least some of the outer folds constituting the bellows generally constitutes an irregularly shaped polygon accepting a single axis of symmetry.

According to a particular embodiment, the outer peripheral contour of at least some of the outer plies is symmetrical with respect to the median horizontal longitudinal plane (HH ') and for each of said plies at least two of the sides of said contour are therefore substantially of the same length.

According to a variant of the embodiment described above the outer peripheral contour of at least some of the outer plies is symmetrical with respect to the median horizontal longitudinal plane (HH ') and three of the sides of said contour are substantially of the same length.

According to another characteristic of another embodiment, the outer peripheral contour of at least some of the outer folds of the bellows generally constitutes a totally asymmetrical polygon, and therefore does not accept any axis of symmetry, and the length of the largest of the sides. said contour is greater by more than one-tenth of that length to that of the longer one of the other sides of the outer contour of the outer fold concerned.
According to an alternative embodiment, the length of the largest of the sides of the outer ply concerned is greater by more than 10% of its length, preferably greater by more than 15% of its length and in particular greater by more than 20% of its length. to the individual length of each of the other sides.

According to another characteristic of an embodiment, at least one of the sides of the outer peripheral contour of at least some of the outer plies constituting the bellows is of curvilinear shape convex in the longitudinal direction of said side over most of the length of said side.

According to another characteristic, at least one of the sides of the outer peripheral contour of at least some of the outer plies constituting the bellows is concavely curvilinear in the longitudinal direction of said side over most of the length of said side.

According to another feature of a particular embodiment at least one of the sides of the outer peripheral contour of at least some of the outer plies constituting the bellows has concave portions and convex portions extending in the longitudinal direction of said side on most of the length of said side.

According to one embodiment, the folds of the bellows consist of two closed frames which are sealingly interconnected at their corresponding inner peripheral edges while the outer edges of the first of said two closed frames are sealingly connected to the outer edges. corresponding sides of the adjacent frame to form therewith the adjacent outer fold located on one side of the aforementioned inner fold while in the same way the outer edges of the second of said two closed frames mentioned above are sealingly connected to the corresponding outer edges of the frame neighbor to form the adjacent outer fold located on the other side of the aforementioned inner fold

According to one embodiment, at least some of the inner plies and / or at least some of the outer plies comprise at least one tie rod intended to prevent ovalization of the bellows during folding of the bellows, resulting in a rise in pressure of the air confined to the inside of the bellows said tie rod being disposed inside the bellows and connecting the inner edge of the inner or outer fold concerned to the diametrically opposite inner edge of the same fold. This tie may be either flexible and elastically deformable or otherwise inextensible according to whether, respectively, the outer contour of the outer folds is rigid and inextensible while the inner folds have bellows arranged in their angles and or that, on the contrary, the inner contour of the inner ply is rigid and inextensible while the outer contour of the outer plies has in its corner areas arrangements allowing it variations in length during the opening and closing movements of the bellows of the instrument.

• les plis du soufflet sont réalisés par injection de deux types de matières thermoplastiques présentant des caractéristiques mécaniques différentes ,
• chaque pli comporte une structure rigide ou semi-rigide, constituée d'au moins un cadre extérieur et d'au moins un cadre intérieur, réalisés par moulage d'une première matière thermoplastique présentant la rigidité requise ,
• les dimensions extérieures hors tout du (ou des) cadre(s) intérieur(s) sont inférieures aux dimensions intérieures hors tout du (ou des) cadre(s) extérieur(s) concernés
• les flancs du pli concerné sont constitués par une membrane étanche réalisée en matière thermplastique souple et élastiquement déformable reliant un cadre extérieur à un cadre intérieur
• les faces latérales des cadres extérieurs et/ou des cadres intérieurs sont en partie au moins recouvertes de la matière souple susmentionnée pour constituer des amortisseurs souples évitant les bruits d'impact de l'une contre l'autre desdites faces latérales lorsqu'elles viennent en contact lors de la fermeture complète du soufflet.

According to one embodiment:

• the folds of the bellows are made by injection of two types of thermoplastics having different mechanical characteristics,
• each fold comprises a rigid or semi-rigid structure, consisting of at least one outer frame and at least one inner frame, made by molding a first thermoplastic material having the required rigidity,
• the overall outside dimensions of the inside frame (s) are smaller than the overall inside dimensions of the outside frame (s) concerned
• the flanks of the fold concerned are constituted by a waterproof membrane made of flexible and elastically deformable thermoplastic material connecting an outer frame to an inner frame
• the lateral faces of the outer frames and / or the inner frames are partly at least covered with the aforementioned flexible material to form soft dampers avoiding the impact noises of one against the other of said side faces when they come into contact when the bellows is completely closed.

According to another characteristic, the inner plies and / or the outer pleats comprise indentations made in the zones of interior angles and / or in zones of outside corners of the folds to allow by shortening and / or by elongation the adaptation of the length of the corner zones of said outer plies and / or said inner plies to the variations imposed by the opening and closing movements of the bellows.
According to another characteristic of a particular embodiment certain sides at least the folds of the bellows are of gradually decreasing dimensions as one moves away from the side of the edge of the keyboard to get closer to the side of the keyboard. accompaniment so that these sides of said folds located in the vicinity of the end of the bellows disposed on the side of the accompanying keyboard are therefore of smaller dimensions than are the corresponding sides of the folds of the bellows located in the vicinity of the end of the bellows arranged on the side of the keyboard.

According to another characteristic of an embodiment variant at least some sides of the folds of the bellows are of gradually decreasing dimensions as one moves away from the edge of the edge of the keyboard to get closer to the keyboard side. accompanying and the degressivity of the lengths of the sides of said folds is homothetic so that the outer peripheral contour of the outer fold located closest to the accompanying keyboard is a homothetic reduction of the outer peripheral contour of the outer fold located closest to the keyboard of song.

According to a particular embodiment relating in particular to accordions of the digital type whose sounds are digitally generated by very compact electronic devices allowing a significant reduction of the dimensions of the boxes supporting the singing keyboard and accompanying keyboard some to less dimensions of the folds of the bellows are of gradually increasing dimensions when one moves away from the end of the bellows located on the edge of the edge of the keyboard to get closer to the central folds positioned midway length of the bellows from which said dimensions of folds are of gradually decreasing dimensions as one moves away from said central folds to approach the end of the bellows located on the side of the keyboard accompaniment.

According to a variant of this embodiment, the folds constituting the bellows are of degressive dimensions symmetrically with respect to the central folds located at mid-length of the bellows so that as one moves away on either side of said central folds the height and / or the overall width of the folds decrease gradually symmetrically.

According to a characteristic of a particular embodiment, the edge pad and / or the accompanying keyboard are arranged obliquely with respect to the median vertical transverse plane ZZ 'such that the line passing through a row of buttons of the one and / or the other of these two keyboards form with the median vertical transverse plane ZZ 'an open angle towards the bottom or on the contrary an open angle upwards according to the position perceived as the most ergonomic for the conditioned player by the high or low position and horizontally or on the contrary inclined downwards that it adopts for the immobilization on his torso of the fixed part of the instrument supporting the keyboard of singing thanks to the straps of the instrument.
According to another characteristic when the breaths considered are completely closed, for the record, except in their corner areas, the bellows of the prior art consist of juxtaposed folds whose longitudinal edges rectilinear inner folds extend parallel at the rectilinear outer longitudinal edges of the outer plies so that, in all these rectilinear areas of the folds, the plies thus have substantially the same depth over the entire periphery of the closed frames they constitute, with the exception of said corner zones, on the other hand, the bellows according to the invention is characterized in that, if not all the faces, at least some of the faces of said bellows consist of internal folds whose longitudinal edges, which, in the longitudinal direction of said folds, can to be rectilinear or on the contrary curvilinear concave or convex, are not parallel to the outer edges external folds so that the depth of the folds is therefore not the same over the entire periphery of the bellows.
According to a preferred embodiment, at least some faces of the bellows according to the invention consist of internal folds whose edge of the dihedral is rectilinear in the longitudinal direction while the corresponding outer longitudinal edges of the adjacent outer folds are curvilinear convex in the longitudinal direction so that the depth of said folds is therefore smaller in the vicinity of the bellows angles than is the depth of said folds in the central zone of the longitudinal sides concerned closed frames formed by said folds.
Such an arrangement proves very interesting from the technical point of view since it makes it possible to offer an optimal compromise between the lowest possible weight of the bellows by reducing height and thus material in the bellows corner zones and a height more important in the central areas of the faces thus providing greater inertia and therefore an optimal resistance to the ovalization of said central zones of the faces of the bellowsface to the internal overpressures during closing movements as well as an optimal resistance by vault effect to the effects of cavitation tending to concave the faces of the bellows during the depression prevailing inside the bellows during opening movements of the bellows.

Brief description of the drawings

• ▪ Les figures 1 à 5 montrent un accordéon de l'art antérieur,
• ▪ Les figures 6 à 13 montrent un premier mode de réalisation d'un accordéon selon l'invention parmi lesquelles :
  • Les figures 6, 7, 8 et 10 sont des vues respectivement du côté droit de l'accordéon, de face, du côté gauche de l'accordéon et de dessus.
  • Les figures 9,11 et 12 correspondent à une section droite du soufflet selon le plan vertical transversal médian ZZ' des figures 7 et 10.
  • La figure 13 montre des agrandissements de deux zones d'angle du soufflet représenté sur les figures ci-avant.
• ▪ Les figures 14 à 17 représentent des sections droites selon le plan vertical transversal médian ZZ' de différentes configurations de soufflet de formes polygonales comptant 4, 5 ou 6 cotés rectilignes.
• ▪ Les figures 18 à 22 représentent des sections droites selon le plan vertical transversal médian ZZ' de différentes configurations de soufflet de formes polygonales comptant 3,4 ou 5 cotés dont certains au moins sont curvilignes.
• ▪ La figure 23 représente un premier mode de réalisation d'un élément d'un soufflet montré plus en détail sur les vues 24, 25, 26 et 27. La figure 28 montre une variante de réalisation faisant appel à un joint d'étanchéité interposé entre 2 plis contigus.
• ▪ Les figures 29 et 30 montrent un second mode de réalisation de l'élément de soufflet présenté sur les vues 23 à 28.
• ▪ Les figures 31 à 34 représentent des coupes transversales de plis contigus montrant un premier mode de réalisation des plis selon l'invention dont les figures 35 à 38 montrent une variante dans laquelle des éléments raidisseurs sont intégrés dans le pli intérieur et dans le pli extérieur au moins dans les zones médianes des grands côtés du soufflet qui sont les plus sollicitées en flexion lors des pressions et des dépressions qui règnent à l'intérieur du soufflet selon que celui-ci est en phase d'ouverture ou de fermeture.
• ▪ Les figures 39 et 40 représentent des coupes transversales partielles de plis montrant un second mode de réalisation d'éléments de soufflet selon l'invention dont chacun des plis intérieurs est constitué d'un élément en forme de Y monolithique.
• ▪ Les figures 41 et 42 représentent des coupes transversales partielles de plis montrant un troisième mode de réalisation d'éléments de soufflet selon l'invention comportant des parties souples et des parties rigides qui peuvent être avantageusement réalisés en bi-injection d'un thermoplastique souple élastiquement déformable surmoulé sur une structure rigide
• ▪ Les figures 43 et 44 représentent des sections droites selon le plan vertical transversal médian ZZ' d'un mode de réalisation d'un soufflet ayant la forme d'un quadrilatère irrégulier dont tous les côtés sont curvilignes et dont le contour périmétrique des plis intérieurs est sensiblement inextensible tandis que le pourtour périmétrique des plis extérieurs comporte des zones d'angle configurées de telle manière qu'elles puissent être élastiquement déformables de plusieurs millimètres pour s'adapter aux variations de longueurs qui leurs sont imposées par les mouvements de fermeture et d'ouverture du soufflet.
• ▪ Les figures 45, 46 et 47 représentent des sections droites selon le plan vertical transversal médian ZZ' d'un second mode de réalisation d'un soufflet ayant la forme d'un quadrilatère irrégulier dont tous les côtés sont curvilignes et dont le pourtour périmétrique des plis extérieurs est sensiblement inextensible tandis que le pourtour périmétrique des plis intérieurs comporte des zones d'angle configurées de telle manière qu'elles puissent être élastiquement déformables de plusieurs millimètres pour s'adapter aux variations de longueurs qui leurs sont imposées par les mouvements de fermeture et d'ouverture du soufflet.
• ▪ Les figures 48 à 53 montrent un premier mode particulier de réalisation d'un accordéon selon l'invention dont la hauteur du soufflet est graduellement dégressive lorsqu'on s'éloigne de l'extrémité du soufflet située du côté du clavier de chant de l'accordéon pour se rapprocher de l'extrémité du soufflet située du côté du clavier d'accompagnement.
• ▪ Les figures 54 à 59 montrent un second mode particulier de réalisation d'un accordéon selon l'invention dont la largeur du soufflet est graduellement dégressive lorsqu'on s'éloigne de l'extrémité du soufflet située du côté du clavier de chant de l'accordéon pour se rapprocher de l'extrémité du soufflet située du côté du clavier d'accompagnement
• ▪ Les figures 60 à 65 montrent un troisième mode particulier de réalisation d'un accordéon selon l'invention dont la largeur et la hauteur du soufflet sont graduellement dégressives lorsqu'on s'éloigne de l'extrémité du soufflet située du côté du clavier de chant de l'accordéon pour se rapprocher de l'extrémité du soufflet située du côté du clavier d'accompagnement
• ▪ Les figures 66 à 68 montrent des modes particuliers de réalisation d'un accordéon selon l'invention dont le clavier de chant et le clavier d'accompagnement sont disposés obliquement par rapport au plan transversal médian Z'Z
• ▪ les figures 69 à 72 correspondent à des coupes transversales partielles de plis contigus d'un soufflet dont la hauteur et/ou la largeur est (ou sont) graduellement dégressive(s) .

Other advantages and features will emerge more clearly from the following description of the various embodiments shown by way of nonlimiting examples and represented in the appended drawings among which:
Among the drawings shown on the attached pages:

• ▪ The Figures 1 to 5 show an accordion of the prior art,
• ▪ The Figures 6 to 13 show a first embodiment of an accordion according to the invention among which:
  • The Figures 6, 7, 8 and 10 are respectively views of the right side of the accordion, front, left side of the accordion and from above.
  • The figures 9,11 and 12 correspond to a cross section of the bellows according to the median transverse vertical plane ZZ 'of Figures 7 and 10 .
  • The figure 13 shows enlargements of two corner areas of the bellows shown in the figures above.
• ▪ The Figures 14 to 17 represent straight sections in the median transverse vertical plane ZZ 'of different bellows configurations of polygonal shapes with 4, 5 or 6 straight sides.
• ▪ The Figures 18 to 22 represent straight sections in the median transverse vertical plane ZZ 'of different bellows configurations of polygonal shapes with 3.4 or 5 sides, at least some of which are curvilinear.
• ▪ The figure 23 is a first embodiment of an element of a bellows shown in more detail in views 24, 25, 26 and 27. The figure 28 shows an alternative embodiment using a seal interposed between 2 adjacent folds.
• ▪ The Figures 29 and 30 show a second embodiment of the bellows element shown in views 23 to 28.
• ▪ The Figures 31 to 34 represent cross-sections of adjacent folds showing a first embodiment of the folds according to the invention, the Figures 35 to 38 show a variant in which stiffening elements are integrated in the inner fold and in the outer fold at least in the central zones of the long sides of the bellows which are the most stressed in bending during pressures and depressions that prevail inside the bellows according to whether it is in the opening or closing phase.
• ▪ The Figures 39 and 40 are partial cross sections of folds showing a second embodiment of bellows elements according to the invention, each of the inner folds consists of a monolithic Y-shaped element.
• ▪ The Figures 41 and 42 represent partial cross sections of folds showing a third embodiment of bellows elements according to the invention comprising flexible parts and rigid parts which can be advantageously made by bi-injection of a flexible elastically deformable thermoplastic overmolded on a structure rigid
• ▪ The Figures 43 and 44 represent straight sections in the median transverse vertical plane ZZ 'of an embodiment of a bellows having the shape of an irregular quadrilateral, all sides of which are curvilinear and whose perimetric contour of the inner folds is substantially inextensible while the perimetric contour of the outer plies comprises corner zones configured in such a way that they can be elastically deformable by several millimeters to adapt to the length variations imposed on them by the closing and opening movements of the bellows.
• ▪ The Figures 45, 46 and 47 represent straight sections in the median transverse vertical plane ZZ 'of a second embodiment of a gusset having the shape of an irregular quadrilateral, all sides of which are curvilinear and whose perimetric periphery of the outer folds is substantially inextensible while the perimetric periphery of the inner plies comprises angular zones configured in such a way that they can be elastically deformable by several millimeters to adapt to the length variations imposed on them by the closing and opening movements of the bellows.
• ▪ The Figures 48 to 53 show a first particular embodiment of an accordion according to the invention, the height of the bellows is gradually degressive when one moves away from the end of the bellows located on the side of the edge of the accordion's keyboard to get closer to the end of the bellows located on the side of the accompanying keyboard.
• ▪ The Figures 54 to 59 show a second particular embodiment of an accordion according to the invention, the width of the bellows is gradually degressive when moving away from the end of the bellows located on the side of the accordion's keyboard to get closer to the end of the bellows on the side of the accompanying keyboard
• ▪ The Figures 60 to 65 show a third particular embodiment of an accordion according to the invention, the width and height of the bellows are gradually degressive when one moves away from the end of the bellows located on the side of the accordion edge keyboard for get closer to the end of the bellows located on the side of the accompanying keyboard
• ▪ The Figures 66 to 68 show particular embodiments of an accordion according to the invention of which the keyboard and accompaniment keypad are arranged obliquely relative to the median transverse plane Z'Z
• ▪ the Figures 69 to 72 correspond to partial cross sections of contiguous folds of a bellows whose height and / or width is (or are) gradually degressive (s).

Detailed description of several embodiments :

It is specified that, in the following figures, to avoid any ambiguity concerning the position of the land-catching landmarks, taking into account the greater or lesser radii of the rounded angles used for the connection between them of the different faces of the bellows, the odds of lengths of the polygon sides corresponding to the outer perimetric perimeter of the straight sections of the various proposed bellows will be counted from the virtual vertices of said polygons. These virtual vertices are formed by the intersection of the lines passing by the sides of said polygons in the case of polygons whose sides are rectilinear while these virtual vertices are constituted by the intersection of the curvilinear extensions of the sides of said polygons when they are of the curvilinear polygon type. In the case of polygons having rectilinear sides and curvilinear sides the virtual vertex located between a rectilinear side and a curvilinear side will be constituted by the intersection of the rectilinear extension of the rectilinear side with the curvilinear extension of the curvilinear side concerned.

The views 1 to 5 show an accordion of the prior art comprising a bellows 2 whose right end is connected to a first box supporting the main keyboard 3 also called melody keyboard or keyboard, consisting here of buttons arranged in lines and offset in staggered relation to each other while the left end of the bellows is connected to a second box supporting the bass keyboard 4 or keyboard accompaniment. The figure 2 , corresponding to the transverse section of the bellows 2 in the mean transverse vertical plane ZZ ', shows that said bellows 2 is higher than wide and that it is of parallelepipedal rectangle shape its sides being parallel in pairs and of identical lengths two to two two while these four interior angles are all right angles. The overall height of the bellows 2 as its overall width remain constant over the entire length of the bellows which means that all the outer plies which constitute this bellows are identical in shape and dimensions and that all the inner folds which constitute this bellows are they are also identical in shape and size.

The Figures 6 to 13 show a first embodiment of an accordion 1 according to the invention comprising a bellows 5 disposed between a first box supporting the main keyboard or keyboard of song or melody 6 and a second box supporting the keyboard accompaniment or keyboard bass 7.
The peripheral contour of the cross section of the bellows 5 along the median transverse vertical plane ZZ 'is a polygon which is here of the overall shape of an irregular-type pentagon since it does not accept any plane of symmetry with its angles at the apex. not all being equal, its sides not all having the same length and none of its sides being parallel to another side.
The five sides of said polygon are rectilinear and they are connected to each other by their ends by means of deformable corner elements (5010, 5020, 5030, 5040, 5050) so that they can allow the variations of the lengths different sides of said polygon associated with movements of angular movements opening and closing of the flanks of the folds of the bellows during the elongation and folding movements of said bellows. The corner elements advantageously consist of a flexible and deformable material different from the more rigid material constituting the flanks of the inner folds and outer folds said folds in front of them, offer in their longitudinal direction a good alternating flexural strength under the effect of alternating pressure and vacuum prevailing inside the bellows during opening and closing movements of the bellows.
It is recalled that the various reference points taken into account for calculating the lengths of the sides L1, L2, L3, L4, L5 of the polygon corresponding to the cross section of the bellows 5 correspond to the positions of the virtual vertices (501, 502, 503, 504, 505) of said polygon located at the intersection of the lines passing through the faces of said sides of the polygon.

Thus, the rear face of the bellows 5 is flat and disposed substantially vertically as shown by the rectilinear character of the rear side of the vertically disposed polygon and whose length L5 corresponding, in this configuration, to the overall external height of the bellows 5, is greater than more than 10% of its value, preferably greater than 15% of its value and in particular more than 20% of its value greater than the length L2 of the longer of the other outer sides of the polygon corresponding to that same section transverse right of the bellows 5.
It will also be noted that the length L5 of the outer rear side of the polygon is at least 10% less than the cumulative length of the lengths L2 and L3 of the two outer front sides of the polygon corresponding to the front face of the bellows 5.

The overall width Lt of the bellows measured horizontally, therefore in a direction parallel to the average horizontal plane HH ', is greater by more than 10% of its value, preferably greater by more than 15% of its value and in particular by more than 20% of its value, the length L1 of the outermost side of the polygon corresponding to the cross section of the upper face of the bellows 5 and this overall width Lt is also greater by more than 10% of its value, preferably greater than more than 15% of its value and in particular greater than 20% of its value, the length L4 of the lower outer side of the polygon corresponding to the same cross-section of the bellows 5, said length L4 corresponding to the width of the base lower bellows.
As shown in figure 12 the three apex angles, A1, A2, A3 are all obtuse angles, therefore of a value greater than 90 ° and they correspond to the aperture angles, respectively, between the upper face of the bellows and the upper part of the front face of the bellows for the apex angle A1, between the upper part of the front face of the bellows and the lower part of the front face of the bellows for the angle at the apex A2, and between the lower part of the front face of the bellows and the bottom face of the bellows for the apex angle A3. On the other hand, the angle A4 corresponding to the angle at the apex between the lower face and the rear face of the bellows is a right angle and the angle A5 corresponding to the angle at the apex between the rear face and the upper face of the bellows. is an acute angle of less than 90 °.
The angles D51, D52, D53, D54 of the dihedrons formed by the planes passing through the virtual vertices of the polygon are all angular values different from each other and the vertices of these dihedrons are all located in the front half-space delimited by the vertical plane P5 tangent to the rear face of the bellows 5.
This configuration makes it possible to clear the field of view of the accordionist forwards and downwards, the upper face of the bellows 5 being inclined downwards and forwards and therefore facing forward while the lower face of the bellows bellows 5 is disposed perpendicularly to the rear face of the bellows to allow the instrument to be "standing" on a horizontal support.

This configuration in which the front face of the bellows comprises both an upward front upper part of length L2 and a lower front part of length L3 pointing downwards also offers the advantage of an optimal acoustic projection towards the forward, spatially both upwards and downwards, sounds emitted at the level of the facades of the pedestal and accompaniment situated in the coplanar extension of said front faces of the bellows 5.
The figure 13 corresponds to enlargements of two corner regions of the bellows shown in the figures above showing that said connection angle zones of the longitudinal sides here rectilinear of the outer folds of the bellows 5 are of rounded shape along radii R5, R6 d a value of between 50% (fifty percent) and 150% (one hundred and fifty percent) of the depth of said outer plies.

The Figures 14 to 17 represent straight sections along the median transverse vertical plane ZZ 'of different bellows configurations 8, 9, 10, 11, of polygonal shapes with 4, 5 or 6 straight sides.
The figure 14 shows a bellows 8 of polygonal cross section of which none of the four sides is of the same length, said sides being therefore all of different lengths. The four corners of the polygon thus constituting its four vertices are not rounded but chamfered according to a chamfer arranged symmetrically with respect to the bisector of the angle at the vertex concerned.
In order to clear the visual field of the accordionist forwards and downwards, the upper face of the bellows 8 is inclined forwards and downwards and therefore oriented upwards and forwards while adopt a more ergonomic playing position for some accordionists playing in sitting position cross-legged the lower face of the bellows 8 is inclined upwards and forwards and therefore oriented downwards and as shown by the dihedron D82 , constituted by the two half-planes passing through said upper and lower faces of the bellows, whose virtual edge is located in front of the front face of said bellows 8. Again to allow a better acoustic projection upwards and towards the before sounds emitted at the level of the facades of the caissons located in the coplanar extension of the front face of the bellows, the front face of the bellows 8 is oriented upwards and forwards as evidenced by the dihedron D81, constituted by the two half-planes passing through said front face and the rear face of the bellows, whose virtual edge is located above the upper face of the bellows.

The figure 15 is a straight cross section of a bellows 9 according to the invention, said right cross section is of the general shape of an irregular polygon with 5 rectilinear sides of which three, respectively 90.91 and 93 are substantially of the same length. The front face of the bellows 9 has an upper part oriented upwards and a lower part facing downwards, the upper part of the front face being of a greater height than the lower part of the front face of the bellows. The five angles of the polygon are chamfered by a rectilinear chamfer arranged symmetrically with respect to the bisector of the angle at the vertex concerned.

The figure 16 is a right cross section of a bellows 10 according to the invention, said right cross section is of the general shape of an irregular polygon with 5 rectilinear sides. The front face of the bellows 10 has an upper portion oriented upwards and a lower portion facing downwards, the lower portion of the front face being of a greater height than the upper part of the front face of said bellows 10.

The figure 17 is a right cross section of a bellows 11 according to the invention, said right cross section is of the general shape of an irregular polygon with 6 rectilinear-type sides said polygon accepting a single plane of symmetry represented by the median horizontal plane HH . In this configuration, the rear face of the bellows 11 is flat and arranged substantially vertically and is moreover disposed substantially perpendicular to the upper and lower faces of the bellows, which are therefore horizontal and parallel to one another. The front face of the bellows 11 has an upper part oriented upwards, a middle portion disposed substantially vertically and therefore substantially parallel to the rear face of the bellows and a lower part facing downwards. The upper and lower portions of the front face are of equal length, respectively L111 measured in the vertical plane of the cross section, said length being here greater than the width of the vertical portion of the front face.

The Figures 18 to 21 inclusive are straight sections in the mean transverse vertical plane ZZ 'of different bellows configurations of polygonal shapes with 3, 4 or 5 sides, at least some of which are curvilinear in the longitudinal direction of the sides concerned.
So the figure 18 shows a cross section of a bellows 12 made according to a first preferred embodiment wherein said right cross section of the bellows consists of a triangular curvilinear shape offering the advantage of an optimal clearance of the visual field of the accordionist. The convexly curvilinear front face is oriented upward and forward to ensure optimum sound projection upward and forward. The underside, also convex curvilinear shape, is oriented forward and down to ensure optimum comfort sitting game. The back is curvilinear slightly concave to provide maximum ergonomics by spreading the support of the instrument over a larger part of the torso than a conventional flat back face allows. The upper face is rounded to a large radius R preferably greater than 50 mm, preferably greater than 70 mm, in particular greater than 100 mm. Internal bellows, not shown, arranged radially with respect to the center of said radius R allow the lengths of the inner peripheral contours of the inner plies to be adapted to the variations imposed on them by the opening and closing movements of the bellows.
The angles D121, D122, D123 of the three dihedra whose planes pass through the virtual vertices 1210, 1220, 1230 of the triangle are all of different angular values. The three sides of the curvilinear triangle are also of different lengths from each other.

The figure 19 shows a cross section of a bellows 13 made according to a second preferred embodiment wherein said right cross section of the bellows consists of a quadrilateral whose peripheral contour has four sides all of curvilinear shape. The upper face of the bellows 13 is of convex curvilinear shape and is slightly inclined towards the front to release at best the visual field of the accordionist. The convexly curvilinear front face is oriented upward and forward to ensure optimum sound projection upward and forward. The underside, also convex curvilinear shape, is oriented forward and down to ensure optimum comfort sitting game. The rear face is curvilinear slightly concave to provide maximum ergonomics by spreading the support of the instrument over a larger part of the torso than does a conventional flat rear face. The angles D131, D132, D133 of the three dihedra whose planes pass through the virtual vertices 1310, 1320, 1330, 1340 of the curvilinear quadrilateral are all of different angular values. The opening angle dihedral D133 opening downwards confirms that the bellows is therefore of generally trapezoidal conical shape, the width of its lower part being greater than the width of its upper part. Compared to the bellows of the prior art such an arrangement allows to refine the upper part of the bellows and therefore the instrument and substantially reduce its overall height while maintaining for the bellows a large volumetric capacity thanks to the enlargement its lower part which also contributes to lowering its center of gravity. In this preferred configuration, the four sides of the curvilinear quadrilateral are also of different lengths. Tie rods 1300, 1301 connect the inner rear edge of at least some of the inner plies to the inner edge before the inner plies concerned.

The figure 20 shows an alternative embodiment of the preferred embodiment described above. In this embodiment, the right cross section of the bellows 14 consists of an irregular pentagon whose outer peripheral contour comprises three sides. of curvilinear shape and two rectilinear sides. The lower face of the bellows is disposed substantially perpendicular to the flat rear face of said bellows to allow the instrument to be placed on a horizontal support in its vertical position as shown in this figure 20 . Pulling 1400 and 1401 connect the two opposite inner edges of the inner folds of at least some of the elements constituting the bellows 14.

The figure 21 shows a right cross section of a bellows 15 in which said section consists of a polygon whose peripheral contour comprises three straight-shaped sides thus showing that the rear face of the bellows 15 as well as its lower and upper faces are flat while the front face has a curvilinear shape of semi-elliptic straight section. This configuration of the bellows 15 is therefore symmetrical with respect to a single plane, the average longitudinal horizontal plane HH 'as is also the configuration of the bellows 16 presented on the figure 22 . The upper and lower faces of the bellows 16 are curvilinear and respectively oriented upwards and forwards for the upper face and downwards and forwards for the lower face, while the front and rear faces are rectilinear and arranged vertically. and parallel to each other

The Figures 23 to 30 show in more detail one of the preferred embodiments of a bellows 17 according to the invention. As shown in figure 24 showing an enlarged horizontal section of several contiguous folds along the AA cross-section markings of the figure 23 the edges of said inner and outer folds constituting the rear portion of the bellows 17 are all straight, said folds being made according to the traditional method of manufacturing consisting of successive folds in successive continuous waves identical and parallel to each other of a material made of sheet such as cardboard or plastic sheet. The folds constituting this rear face of the bellows are therefore of constant depth P9 along their length except in the zones of angles of connection with the upper face and the lower face of the bellows. The figures 25 and 27 show enlarged details corresponding to a cross section according to the BB marks of several adjacent folds explaining the embodiment of the other three sides of the bellows 17. according to this first embodiment the lower face, the front face and the upper face of the bellows 17 are constituted by internal folds 170, 171 independent of each other each consisting of a V-shaped folded sheet material according to a first central fold 1700, 1710 constituting the rectilinear edge of articulation of the two faces movable in pivoting of the fold interior concerned while each of the two wings of the V is then folded according to an intermediate fold 1701, 1702, 1711 and 1712 so that the parts of said wings extending between said intermediate folds and the ends of said wings can be brought parallel to each other relative to others . Each of the inner plies 170 thus produced and secured to the adjacent inner ply 171 by a profiled sealing element 174 U-shaped inverted gasket serving as a seal against air leakage that caps the adjacent upper parts of two adjacent folds. Rivets 173 ensure at the same time the holding in place of the seal 174 and the mechanical connection of the folds between them to avoid, when the bellows is stretched, that each of the folds deviates from the adjacent fold to which it is attached . In this embodiment the hinge edge pivoting movable walls of the inner fold concerned constituted by the fold 1700,1710 is rectilinear while the outer edges 1703, 1704, 1713, 1714 constituting the ends of the wings of said folds, are advantageously cut in a curvilinear pattern to closely follow the outer shape itself curvilinear in the longitudinal direction of the outer edge of the outer folds as shown in the broken portion of the figure 26 .
As illustrated by the figure 23 the overall depth dimension P6 of the plies constituting the front face of the bellows measured substantially at mid-length on the side of said plies between the straight edge of the inner ply and the convex curvilinear edge of the outer contour of the outer plies is greater than the P8 dimensions and P9 corresponding to the depths of said folds respectively measured for the P8 dimension in the vicinity of the end of the rectilinear portion of the inner fold located in the vicinity of the junction angle between the front face and the upper face of the bellows and for the P9 dimension near the end of the rectilinear portion of the inner fold located near the junction angle between the front face and the upper face of the bellows.
According to a preferred embodiment, the P9 is advantageously at least 10% (ten percent) higher than P7 and / or P8, preferably at least 15% (fifteen percent) higher than P7 and / or at P8 and in particular at least 20% (twenty percent) greater than P7 and / or P8.
This arrangement makes it possible to offer an optimal compromise between the smallest possible weight of the bellows by reducing height and therefore material in the bellows corner zones and a greater height in the central zones of the faces thus offering greater inertia. and therefore an optimal resistance to the ovalization of said central zones of the bellows faces face internal overpressures during closing movements as well as an optimal resistance by vault effect to the effects of cavitation tending to concave the faces of the bellows when the depression prevailing inside the bellows during opening movements of the bellows.
The outer connection angles of two contiguous longitudinal sides of the outer plies are rounded along the radii R1, R2, R3, R4 all of which are between 50% (fifty percent) and 150% (one hundred and fifty percent) of the depth of the fold measured in the immediate vicinity of the angle concerned, so the radius R2 is between half and one and a half times the value of P8 while the radius R3 is between half and one time and the value of P7.
The figure 26 shows that the outer contour of the outer folds constituting the relevant face of the bellows is convexly curvilinear in the longitudinal direction of said folds. The arrow F3 of said bellows face is measured between the point 1752 furthest from the outer contour of the outer fold concerned and the line MM 'passing through the two imaginary angles 1750 and 1751 constituted by the intersections of the curvilinear extensions of the concerned side of said fold. outer and curvilinear extensions of the two sides adjacent to said outer fold concerned. The value of the arrow F3 is advantageously greater than 3% (three percent) of the value of the distance L7 separating the two fictitious points 1750 and 1751 as defined above, this value of the arrow F3 may preferably be greater than at 7% (seven percent) of the length L7 and in particular be greater than 10% (ten percent) of the length L7.

The figure 28 shows an alternative embodiment in which the sealing member 18 is profiled in the general shape of a T which may advantageously be made in part at least in a slightly flexible material. The central portion of this profile is interposed between the two contact faces of two adjacent folds to which it is advantageously bonded to ensure a perfect seal against air leakage while the wings of the T-section cover and protect the slices of both walls constituting the outer fold concerned
Bellows 17000 angle allow the enlargement and narrowing of perimeter perimeter edges of the bellows interior bellows during opening and closing of the bellows 17.
The figure 29 and the figure 30 , which is a cross section of several contiguous folds according to the CC marks of the figure 29 show an alternative embodiment in which the inner folds and the outer folds of the relevant faces of the bellows are made using the same continuous strip of folded sheet material according to a rectilinear inner fold 1900, constituting the hinge edge faces of the inner fold concerned, then folded according to a second external folding 1903 of 180 ° '(one hundred and eighty degrees) disposed parallel to the inner folding 1900. The operation is repeated as many times as necessary to achieve the number of inner folds and desired exteriors. Intermediate bends 1901 and 1902 are made between the inner fold 1900 and the outer fold 1903 to which they are also arranged parallel. The two intermediate bends 1901 and 1902 are here both positioned at the same distance from the inner bend 1900 and they constitute the bending folds of the two movable walls constituting the outer bend concerned. It should be noted that these two intermediate folds 1901 and 1902 could however be positioned parallel to each other but each has a different distance from the central ridge 1900 to achieve a bellows degressive dimensions as described in the following pages of this document. These intermediate joint bends 1901, 1902 may advantageously be positioned substantially at the end of the two wings of the U-shaped profiled sealing member 194 which caps the entire part of the movable walls of the outer fold concerned. extending between said intermediate folds 1901 and 1902 and the outermost folding 1903. Rivets 193 provide both the maintenance in place of the seal 194 and the mechanical connection between them of the walls of the outer fold concerned. As the broken part of the figure 29 in this embodiment the hinge edge 1900 of the faces of the inner plies is rectilinear over most of the length of the lower, front and upper faces of the bellows 19 while the outer edge of the outer plies, constituted by the face of the sealing member 194 facing the outside of the instrument, is curvilinearly shaped over most of the length of each of said sides.

The Figures 31 to 34 1 show another embodiment of the elements of the bellows of the accordion according to the invention firstly using two subassemblies 50, 51, shown in FIG. figure 31 in cross section, which have the form of closed frames totally symmetrical with respect to each other and whose shape and external dimensions correspond to the desired shapes and external dimensions for the bellows .These two subassemblies made very well. The thermoplastic injection molded in a mold are secured to each other in a sealed manner in the vicinity of their inner edges 500,510 all around their inner peripheral periphery by riveting, stapling, latching, gluing or advantageously by high frequency welding as shown in FIG. figure 32 to constitute an inner fold represented on the figure 33 . After tight assembly of these two elements as shown on the figure 33 the outer edges 501, 511 of one of the two closed frames are sealingly connected to the corresponding outer edges of the adjacent frame belonging to the adjacent bellows element, to form an outer fold as shown in FIG. figure 34 and in the same manner the outer edges of the other of the two abovementioned closed frames are sealingly connected to the corresponding outer edges of the adjacent frame belonging to the adjacent bellows element. It is only necessary to repeat these operations the number of times required to achieve the desired number of folds for the bellows.

The Figures 35 to 38 show an alternative embodiment in which stiffening elements 20 and 21, constituted here of a round rigid wire but which could be of any other shape, metallic or fiberglass or carbon, are integrated in the inner fold and in the external fold at least in the central zones of the long sides of the bellows which are the most stressed in bending during depressions and overpressures that prevail inside the bellows depending on whether it is in the opening or closing phase.

The Figures 39 and 40 show a second embodiment of the elements of the bellows according to the invention using a Y-shaped closed frame-shaped subassembly all over the around said frame to form an inner fold. It then remains only to join together adjacent cheeks of two contiguous elements by any means ensuring a mechanical strength and a total seal such as in particular a high frequency ultrasonic welding to achieve the outer folds of the bellows very quickly and very economic said bellows offering in addition to the bellows of the prior art the advantage of being insensitive to moisture and mold while being also easy to clean.

The Figures 41 and 42 show a preferred embodiment in which the inner plies 22 are made by injection of two types of thermoplastic materials. Each inner ply 22 has a rigid or semi-rigid structure consisting of two identical outer frames 220, 221 and an inner frame 223 all three made by molding a first thermoplastic material having sufficient rigidity. The overall outer dimensions of the inner frame 223 are smaller than the inner dimensions of the two outer frames 220 and 221. The flanks of the bellows element are constituted by two waterproof membranes 224 made of flexible and elastically deformable thermoplastic material connecting each of the two outer frames 220 and 221 to the inner frame 223. The lateral faces of the outer frames 220, 221 and the inner frame 223 are at least partially covered with flexible material to avoid impact noise during the complete closure of the bellows, and small damping cushions 225 made by molding the flexible material during molding of the flexible membranes 224 are advantageously arranged in screws with respect to each other on the lateral faces of the outer frames 220 and 221 coming into contact one against the other during the complete closure of the folds of the bellows. To ensure good bending strength of the inner folds and outer folds to prevent the flanks of the bellows from deforming concavely under the effect of the depression which is created inside the bellows when unfolded or not is ovalized under the effect of the pressure that is created inside the bellows during its folding, the inner frame 223 has an internal metal reinforcement 2230 disposed on at least parts of its periphery. This internal reinforcement here consists of a round wire but it could be of any other form including being constituted by a metal blade or a stiffener of synthetic fiber or injection moldable thermoplastic resin.
Each of the outer frames 220 and 221 is then sealed to the adjacent corresponding frame to form an outer fold of the bellows.
Some of the inner pleats have tie rods 23 disposed within the bellows and connecting an inner edge of said inner ply to the corresponding inner inner edge of the same inner ply. This provision aims to prevent ovalization of the bellows during its folding causing a rise in pressure of the air confined inside the bellows.

The Figures 43 and 44 show an alternative embodiment of a bellows whose outer folds have softening indentations 24 made in their outer corner areas to allow by shortening and lengthening the adaptation of the length of said corner areas of the outer folds to the variations they undergo during the opening and closing of the bellows. Indeed, in this configuration, the area of the folding edge of the inner ply is made of a material sufficiently inextensible so that the peripheral inner periphery of the inner ply concerned is deliberately made almost inextensible of such material that, during the movements of opening and closing of the bellows, the folds of the bellows do not adapt to the length variations imposed on them by lengthening the corner zones of the inner folds, as is the case with the extensible interior angle bellows used in the accordion bellows of the prior art, but results in a narrowing of the corner areas of the outer folds. Internal tie rods 25 connect the two opposite edges of the inner fold concerned.

The Figures 45, 46 as well as figure 47 , which corresponds to an enlarged cross-section along BB of several adjacent bellows elements, show one of the preferred embodiments consisting of particular arrangements of the bellows shape presented in FIG. figure 19 . These arrangements consist in particular of indentations 26 made in the inner corners of the peripheral inner periphery of the inner folds to allow by shortening and lengthening the constant adaptation of the length of the corner zones of the inner folds to the variations which they undergo during the opening and closing of the bellows.
The two adjacent walls each constituting outer plies are here secured together by sealing or sealing mechanically by crimping a peripheral strip 28 of sheet-shaped jumper or by clipping a rigid material profile made of sheet metal. aluminum or steel or a plastic profile with the required mechanical properties. As shown by the enlargement carried out at figure 47 the connecting zones between the two walls of the outer bend concerned comprise complementary shaped reliefs both to allow adjustment and perfect positioning of the two walls relative to each other and also to ensure total waterproofness . Internal reinforcing members 27 disposed within the inner pleats extend over at least a portion of the length of the two longer sides of said inner plies.
In this embodiment, the outer circumferential periphery of the outer plies is advantageously designed so that the dimensions of said periphery can not vary, the length variations imposed by the closing and opening movements of the bellows being effected only when 'at the inner folds using the arrangements described above located in at least some of the corners of the bellows sides.
The Figures 48 to 59 show variants of an accordion according to the invention of which at least some sides of the inner and outer folds constituting the bellows are of gradually decreasing dimensions as one moves away from the end of the bellows located on the edge of the edge of the keyboard to get closer to the end of the bellows. bellows located on the side of the accompanying keyboard. This configuration of the accordion offers a triple interest: on the one hand it reduces the weight of the part of the instrument that must support the arm of the accordionist actuating the bellows, on the other hand the gradual reduction of ratings congestion of the instrument optimally releases the visual field of the player and finally it allows a more nuanced game because the gradual decrease of the dimensions of said bellows allows more finely dosing the pressure or depression inside the bellows and therefore the volume of sound that does not permit a bellows of larger dimensions. Indeed the player can play the pianissimo by gently pressing only the reduced-size part of the bellows located on the side of the keyboard accompaniment while fortissimos will be achieved by soliciting the entire bellows.

So the Figures 48 to 53 show a first version of this particular embodiment in which the overall height of the bellows is degressive, its overall vertical height H1 measured along the plane CC in the vicinity of the end of the bellows located on the side of the edge pad 29 being more It is important that its overall vertical height H2 measured along the plane DD in the vicinity of the end of the bellows situated on the side of the accompanying keyboard 30 while the overall width L1 of the said bellows remains the same throughout the length of the bellows.

The Figures 54 to 59 show a second version of this particular embodiment in which the overall width of the bellows is degressive, its overall width L2 measured horizontally in the EE plane in the vicinity of the end of the bellows located on the side of the edge pad 31 being more important than its overall width L3 measured horizontally in the plane FF near the end of the bellows located on the side of the accompanying keyboard 32 while the overall height H3 of said bellows remains the same throughout the length of the bellows

The Figures 60 to 65 show a third version of this particular embodiment in which the overall width and the overall height of the bellows are degressive. Thus its overall width L4 and overall height H4 measured in the plane GG near the end of the bellows located on the side of the edge pad 33 are respectively larger than its overall width L5 and its overall height H5 measured in the plane JJ near the end of the bellows located on the side of the accompanying keyboard 34.

The configurations presented on the Figures 48 to 59 included all present a accordion according to the invention, the degressivity of the folds relates only to the upper face and / or the front face of the bellows so that, when the bellows is completely folded, at least in the longitudinal direction of the instrument the lower face of the bellows remains substantially perpendicular to each of the two planes passing through the contour of the ends of the folded bellows.

The figure 66 shows an accordion according to the invention, the degression of the folds relates only to the lower face and / or the front face of the bellows so that, when the bellows is completely folded, at least in the longitudinal direction of the instrument the face upper bellows remains substantially perpendicular to each of the two planes passing through the contour of the ends of the folded bellows.

By cons Figures 60 to 65 comprises an accordion according to the invention, the degressivities of the peripheral contours of the outer plies are symmetrical with respect to the plane H'H when said bellows is completely folded so that as shown in FIG. figure 60 when the bellows is completely folded, the box 35 of the instrument supporting the edge pad and the box 36 supporting the accompanying keyboard are then substantially centered in the vertical direction relative to the median horizontal longitudinal plane HH '.
All these provisions of degressivity of bellows described above make it possible to reduce logically the dimensions of the box supporting the accompanying keyboard which due to its compactness compared to the keyboard of song does not require a support box which is the size of the one that the inevitable dimension of the keyboard of song imposes on the support on which this last one is implanted.

As shown by Figures 48 and 50 The edge pad 29 may advantageously be oriented downwards and therefore inclined in such a way that the line passing through a row of buttons forms with the median vertical plane ZZ 'an angular value angle A6 open downwards while the keypad accompaniment 30 is advantageously also directed downwards so that the line passing through a row of buttons of the accompanying keyboard constitutes with the average transverse plane HH 'an angle angle angle A7 open downwards. This amounts to saying that the two lines passing one by a row of buttons of the edge keyboard and the other by a row of buttons of the accompanying keyboard form an angle angle angle A6 + A7 whose opening is directed down.
Such a configuration of the instrument represents an optimal ergonomic fit for playing large accordionists and accordionists who often play standing or walking and thus adopting a low positioning of the instrument on the torso for maximize their visual field forward.

Conversely, Figures 54 and 56 show a more ergonomic reverse keyboard orientation for players who are used to playing seated and thus adopting a higher position of the instrument on the torso. In this configuration, the edge pad 31 may be advantageously upwardly oriented so that the line passing through a row of buttons constitutes with the median vertical transverse plane ZZ 'an upwardly open angle A8 while the keyboard of Accompaniment 32 is also advantageously upwardly oriented such that the line passing through a row of bass buttons constitutes with the median transverse vertical plane ZZ 'an angle A9 open upwards.
For reasons related to his habits and / or his morphology or his particular way of positioning his accordion the directions of the keyboard and accompanying keyboard most comfortable and most ergonomic for the player may be different from those described above and in particular be such that the edge of the keyboard is oriented downwards and the keyboard accompaniment upwards or conversely be such that the keyboard is facing upwards and the keyboard accompaniment oriented the bottom.
So the figure 68 shows a layout of the keyboards such that the edge pad is downwardly oriented at an angular value angle A15 with respect to the median transverse vertical plane ZZ 'while the accompanying keyboard is upwardly oriented at an angular value angle A14 with respect to the median transverse vertical plane ZZ '.
The figure 67 shows an arrangement of the keyboards such that the edge pad is oriented upwards at an angle of angular value A12 with respect to the median transverse vertical plane ZZ 'while the accompanying keyboard is oriented downwards at an angle of angular value A13 with respect to the median transverse vertical plane ZZ '.

In a concern for optimal adaptation of the instrument to the morphology, habits and wishes of the accordionist, according to other embodiments not shown in this document, the keyboard and / or accompaniment keyboard are not arranged on planes positioned substantially vertically as in the accordions of the prior art but on the contrary on inclined planes with respect to the rear face of the bellows. Thus the keyboard and / or the accompanying keyboard can be implanted on a plane (two planes) inclined (s) forwards and downwards so that the line passing through the vertices of the buttons of a line of the keyboard concerned constitutes with the general plane of the rear face of the bellows an open angle upwards or on the contrary the keyboard of the edge and / or the keyboard accompaniment can (can) be implanted (s) ) on a plane (two planes) tilted backwards and upwards in such a way that the line passing through the vertices of the buttons a line of the keyboard concerned then constitutes with the general plane of the rear face of the bellows an open angle downwards. Of course only one of the two keyboards can be tilted in an inclined plane upwards and forwards or on the contrary in a plane inclined towards the bottom and towards the front while the other keyboard is either positioned on a substantially vertical plane in a conventional manner or is instead on the contrary positioned on an inverse plane of inclination of the plane on which the other keyboard extends.

The Figures 66 to 69 show an embodiment of bellows elements whose folds are asymmetrical to allow to achieve a bellows whose overall width and / or the overall height are degressive. To do this, the depths p8 and p9 of the flanks of the folds are different from each other by a value Dp, each fold of the bellows being constituted, on the face or faces of the bellows concerned by said gradual reduction of its dimensions, a depth flank p8 greater than Dp to the depth p9 of its second flank so that gradually the concerned dimension of the bellows is reduced by the value of Dp at each fold.

It should be noted that if the accordions represented on the various views above are of the chromatic keypad type, the present invention also applies on the one hand to accordions whose keyboard is composed of white and black keys d a layout similar to that of the keyboard of a piano and secondly to diatonic accordions as well as concertinas and bandoneons.

Of course, the present invention is not limited to the embodiments shown and described by way of example but it also includes all the technical equivalents and their combinations, if they are implemented within the scope of the following claims. .

Claims (13)

1. Accordion of chromatic or diatonic type comprising:

   - a first keyboard, usually referred to as right-hand or melody manual (6,29,31,33), arranged on one side of the instrument and supported by a first box (35) connected to one of the ends of the bellows, said keyboard enabling the accordionist to play the melody with one hand, being formed either by piano-style keyboard keys comprising white keys and black keys or by a button-style layout with buttons arranged side by side on several rows which may be staggered or not with respect to one another,

   - a second keyboard, usually referred to as left-hand or accompaniment manual (7,30,32,34), arranged on the other side of the instrument and supported by a second box (36) connected to the second end of the bellows, said keyboard enabling the accordionist to play bass notes and chords, with his other hand, to provide the accompaniment and rhythmics of the melody,

   - a bellows (5,8,9,10,11,12,13,14,15,16,17) formed by a juxtaposition of several inner and outer pleats each having the form of a closed frame, which can be designated by the general term of pleats, arranged side by side and joined to one another by their adjacent movable walls so that each of the two movable walls of an inner pleat forms one of the two movable walls of the adjacent outer pleat and vice versa,

   - each of the inner pleats is formed by two movable walls joined to one another by a common edge thereby constituting a dihedron open in the direction of the outside of the bellows, the angle of said dihedron varying from substantially zero degrees when the bellows is completely folded to about 90° or even more when the bellows is fully deployed,

   - and each of the outer pleats is formed by two movable walls joined to one another by a common edge thereby constituting a dihedron open in the direction of the inside of the bellows, the angle of said dihedron varying from substantially zero degrees when the bellows is completely folded to about 90° or even more when the bellows is fully deployed,

   characterized in that the closed peripheral circumference of at least certain of the pleats foming the bellows (5,8,9,10,11,12,13,14,15,16,17) forms a polygon of irregular shape in so far as the sides of said polygon are not all equal to one another nor are they all equal two by two.
2. Accordion according to claim 1 characterized in that the outer peripheral contour of at least certain of the outer pleats of the bellows (5) forms an irregular and asymmetric polygon and in that the length (L5) of the largest of the sides of said outer pleats is greater by more than one tenth of this length than that (L2) of the longest of the other sides of the outer pleats concerned.
3. Accordion according to claim 1 characterized in that at least certain surfaces of the bellows (17) according to the invention are formed by inner pleats the edge of the dihedron of which is rectilinear in the longitudinal direction whereas the corresponding outer longitudinal edges of the adjacent outer pleats are of convex curved shape in the longitudinal direction so that the depth (P7, P8, P11, P12) of said pleats is therefore smaller in the vicinity of the corners of the bellows than the depth (P6,P10) of said pleats in the central area of the longitudinal sides concerned of the closed frames formed by said pleats.
4. Accordion according to claim 1 characterized in that at least one of the sides of the outer peripheral contour of at least certain of the outer pleats of the bellows (12,13) is of convex curved shape in the longitudinal direction of said side on the majority of the length of said side.
5. Accordion according to claim 1 characterized in that at least one of the sides of the outer peripheral contour of at least certain of the elements forming the bellows (12,13) is of concave curved shape in the longitudinal direction of said side on the majority of the length of said side.
6. Accordion according to claim 1 characterized in that the pleats of the bellows are formed by two closed frames (50,51) which are joined to one another in tightly sealed manner at the level of their corresponding inner peripheral edges (500,510) whereas the outer edges (501) of the first of said two closed frames are joined in tightly sealed manner to the corresponding outer edges of the adjacent frame to form with the latter the adjacent outer pleat situated on one side of the above-mentioned inner pleat, whereas in the same way the outer edges (511) of the second of said two above-mentioned closed frames are joined in tightly sealed manner to the corresponding outer edges of the adjacent frame to form the adjacent outer pleat situated on the other side of the above-mentioned inner pleat.
7. Accordion according to claim 1 characterized in that at least certain of the inner pleats and/or at least certain of the outer pleats (13,14) comprise at least one tie rod (1300,1301,1400,1401,23) located inside the bellows and connecting the inner edge of the inner pleat or of the outer pleat concerned to the diametrically opposite inner edge of this same pleat.
8. Accordion according to claim 1 characterized in that:

   - the pleats of the bellows are formed by injection of two types of thermoplastic materials presenting different mechanical characteristics,

   - each pleat comprises a rigid or semi-rigid structure formed by at least an outer frame (220,221) and at least an inner frame (223) formed by moulding of a first thermoplastic material presenting the required rigidity,

   - the overall outer dimensions of the inner frame (or frames) (223) are smaller than the inner dimensions of the outer frame (or frames) concerned (220,221),

   - the flanks (224) of the pleat concerned are formed by a sealed membrane made from flexible and elastically deformable thermoplastic material joining an outer frame (220,221) to an inner frame (223),

   - the lateral surfaces of the outer frames and/or of the inner frames are at least partially covered by the above-mentioned flexible material to form flexible dampers (225) preventing noises of impacts of said lateral surfaces against one another when the latter come into contact when the bellows is completely closed.
9. Accordion according to claim 1 characterized in that the inner pleats and/or the outer pleats comprise indentations made in the inner corner areas (26) and/or in the outer corner areas (24) of the pleats to enable the length of the corner areas of said outer pleats and/or of said inner pleats to be adjusted, by shortening and/or by lengthening, to the variations imposed on them by the opening and closing movements of the bellows.
10. Accordion according to claim 1 characterized in that at least certain sides of the pleats of the bellows are of gradually decreasing dimensions when moving away from the side where the melody manual (33) is situated towards the side where the accompaniment manual (34) is situated, so that these sides of said pleats situated in the vicinity of the end of the bellows located on the side where the accompaniment manual (34) is situated are of smaller dimensions than the corresponding sides of the pleats of the bellows situated in the vicinity of the end of the bellows located on the side where the melody manual (33) is situated.
11. Accordion according to claim 1 characterized in that at least certain sides of the pleats of the bellows are of gradually decreasing dimensions when moving away from the side where the melody manual (33) is situated towards the side where the accompaniment manual (34) is situated, and in that the decrease of the dimensions of said pleats is homothetic so that the outer peripheral contour of the outer pleat situated closest to the accompaniment manual (34) forms a homothetic reduction of the outer peripheral contour of the external pleat situated closest to the melody manual (33).
12. Accordion according to claim 1 characterized in that the melody manual (31) is arranged obliquely with respect to the vertical transverse mid-plane ZZ' so that the line passing through a row of buttons of said melody manual (31) forms an angle (A8) with the vertical transverse mid-plane ZZ' that is open in the upwards direction.
13. Accordion according to claim 1 characterized in that the melody manual (29) is arranged obliquely with respect to the vertical transverse mid-plane ZZ' so that the line passing through a row of buttons of said melody manual (29) forms an angle (A6) with the vertical transverse mid-plane ZZ' that is open in the downwards direction.

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