EP3755920A1

EP3755920A1 - Power transmission belt

Info

Publication number: EP3755920A1
Application number: EP19708423.9A
Authority: EP
Inventors: Pierre-Régis Frey
Original assignee: Imagine
Current assignee: Imagine
Priority date: 2018-02-22
Filing date: 2019-02-22
Publication date: 2020-12-30
Also published as: FR3078127B1; WO2019162455A1; FR3078128A1; FR3078127A1

Abstract

The invention concerns a power transmission belt (10) comprising an open band section (16), delimited by two ends (17, 18), assembled by a junction device (40) cooperating with locking rods (42) so as to be able to be at least partially dismounted, arranged to space apart the teeth (14) of the ends (17, 18) by the pitch (P) of the notched face (12) of said belt (10). The notched belt therefore has two use states: an open state allowing it to be mounted on a closed frame or chassis, and a closed state providing traction resistance at least equal to that of a chain or notched belt manufactured as a closed loop. To this end, it comprises a traction core wound around the locking rods (42) provided in said ends (17, 18), the strands of the cables of which are arranged side by side in the median plane of said belt corresponding to the neutral fibre of same. The junction device (40) of same is designed to observe the regular pitch (P) between the teeth and ensure the meshing of the toothed gears (1, 2).

Description

POWER TRANSMISSION BELT

Technical area :

The present invention relates to a power transmission belt comprising on at least one of its faces, teeth separated by a regular pitch to form at least one toothed face arranged to mesh toothed pulleys of a mechanical transmission, said belt comprising at least one band section provided with said at least one notched face and a tensile core embedded in its thickness to obtain a reinforced belt, said band section being delimited by two ends each provided with a tooth, and at least one transverse through hole or at least one locking pin, the ends of said at least one strip section being assembled by means of at least one connecting device cooperating with at least one locking pin to be at least partially removable, said at least one junction device being arranged to form a belt having two states of use: an open state ert in which the ends of said strip section are not assembled, and a closed state in which the ends of said strip section are assembled by said at least one joining device, said towing core comprising at least one tensile cable wound in turns or in longitudinal loops between the two ends of said strip section at least partially surrounding said at least one transverse orifice or said at least one locking pin.

Prior art:

One of the technical fields which interests, in particular but not exclusively, the invention is that among others two-wheeled vehicles, whether they are non-motorized: like the bicycle, the ATV, or equipped with an auxiliary electric motor such as the electrically assisted bicycle, etc., or whether they are motorized (heat engine or electric motor): such as the solex, the moped, the motorcycle, the moped, scooter, etc. The concept of "two wheels" should not be limiting, as this type of vehicle can be divided into three or four wheels depending on the model. In this type of vehicle, traditionally used as a power transmission member a chain, which is a closed mechanical element consisting of an assembly of a series of metal links for transmitting a movement without sliding between the pedal or the engine and a wheel or an axle. This vehicle application requires the transmission member to transmit high forces, and as an example of the order of 2000N peak effort, to develop a maximum power of about 400W, especially during starting of the vehicle, for a low rotation speed, of the order of 80 to 140 rpm, with a relatively narrow transverse dimension, of the order of 12 mm, and a flexibility allowing it to mesh gears with variable diameters of largest to smallest, of the order of 45mm to l50mm with steps of 8M (8mm) or 11M (l lmm). The chain offers an excellent compromise. In addition, the links of the chain being removable, the chain can be mounted open on the vehicle, which facilitates its implementation on any type of frame or closed frame. In addition, it allows changes in speed by any known system including a derailleur. However, it has disadvantages: it relaxes and wears the gears prematurely, it must be greased regularly, it often derails and clogs quickly, it is dirty and noisy.

One of the alternatives to the chain is a toothed belt, made of a flexible material, such as polyurethane, neoprene-type rubber, or the like, and reinforced with steel, Kevlar®, carbon, fiberglass or similar cables. . Such a toothed belt has many advantages: it is economical, light and quiet, it dampens vibration, shock and transmission shock, it is clean and requires no maintenance, saving time, it does not derail it also has a significantly longer service life than the conventional chain drive system, while offering mechanical performance similar to that of a chain. However, it has the following disadvantages: it is manufactured in closed loop without end, without possibility of opening. It therefore requires a frame or a special frame provided with at least a mechanically removable part to allow the passage of the belt, which has the disadvantage of reducing the rigidity of the frame having the effect of lowering the performance of the vehicle. If to overcome this disadvantage, it seeks to increase the rigidity of the frame by other means, the weight of the vehicle is impacted, also having the effect of lowering its performance. In addition, the toothed belt requires a different gearshift system, integrated into the hub of the rear wheel, because it allows no transverse movement to the reverse of the chain. For this purpose, the toothed belt must be guided longitudinally. For this purpose, the toothed or toothed pulleys of the transmission comprise guiding means, either in the form of flanges providing lateral guidance, or in the form of a central rib providing a central guide. The publication US 2018/010667 A1 proposes a bicycle transmission belt according to the preamble of claim 1. This belt is reinforced by cables wound in a loop around the mounting pins embedded in the ends of the belt. The strands of the cables extend over two parallel plies in the thickness of said belt, spaced apart from each other by the diameter of said mounting shafts. But this belt can not work and / or is not feasible industrially. Indeed, the arrangement of the cables distributed over two parallel sheets requires that the length of the strands located on the inner perimeter is less than the length of the strands on the outer perimeter, if the cables are inextensible. Since each pair of inner and outer strands are part of the same loop that wraps around a mounting axis, the length of the strands tends to equilibrate, so that the industrial realization of such a belt, usually obtained by overmolding, is almost impossible. In addition, when the belt is mounted around the toothed pulleys, the belt describes two rectilinear sections respectively between the two pulleys, in which the parallel strands are of the same length, alternated with two curved sections at the right pulleys, in which the parallel strands are of different lengths. As the belt rotates, the straight sections and the curved sections move continuously. Thus, if the cables are inextensible, the belt can not rotate. Conversely if the cables are extensible or elastic so that the strands on the inner perimeter can compress and the strands on the outer perimeter can stretch allowing the rotation of the belt, the pitch between the teeth of the belt will then function of the force transmitted by this belt and can not be respected, making the gear with the toothed pulleys impossible.

The publication EP 1 333 193 A1 relates to a toothed belt for transporting products, closed by two junction pieces in the form of staples, provided with interlocking teeth, secured to a central layer of said belt, and assembled by a single locking rod housed in a transverse hole formed by said connecting pieces when the teeth are nested one inside the other. It seems difficult or impossible to put the staples of the joining pieces to respect the regular pitch of the teeth of the belt. This type of junction has the disadvantage of locking in the same plane three successive teeth of the belt, thus preventing the belt from wrapping around the pulleys and causing rapid wear of the belt. In addition, this type of junction prevents the creation of a mechanical continuity between the traction core of the belt and the joining parts, prohibiting its application particularly in the field of the vehicle.

The publication JP S59 77146 A proposes an open toothed belt whose ends to be connected are each delimited by a tooth and are assembled by a detachable junction, in the form of a U-shaped stirrup fixed by screws screwed into holes provided. in the teeth. These fixing holes being located in the teeth of the belt are therefore arranged under the reinforcing ply. The junction area obtained therefore has poor mechanical performance, related only to the strength of the material of the belt without involving the reinforcing ply. In Moreover, it does not allow to respect the pitch between the teeth of said ends, the pitch between the two teeth located in the junction zone being necessarily less than the regular pitch of the teeth of the belt. Thus, the current toothed belts and their associated junction system are not entirely satisfactory, the efforts transmitted being very insufficient and the respect of the step is not respected.

In other technical fields and in particular in the industry, toothed belts are also used for power transmission. The specification is however very different from the vehicle application, since the transmission members are generally wider, and as an example of the order of 10mm to 25mm, for steps of 8M (8mm) to 32M ( 32mm), turn faster, and as an example of the order of 1500 or 3000rpm in general, and mesh gears of larger diameter of the order of 40mm to 400mm. However, in both types of application, the problem of the respect of the pitch between the teeth of the belt remains the same to be able to guarantee a perfect meshing with the toothed gears.

Presentation of the invention

The present invention aims to overcome these disadvantages by providing a multi-purpose toothed belt, designed for power transmission in any field of application, said belt being equipped with a simple and fast mechanical joint allowing it to be mounted open in order to allow its implementation on any type of frame or closed frame, therefore no longer requiring modification of said frame to create a passage particularly detrimental to the mechanical strength of the frame or the frame, especially when it is made based on carbon fiber, said toothed belt mechanical junction being furthermore as efficient in terms of mechanical strength, flexibility and slip-free transmission as current toothed belts closed and that the traditional chains, and can be adapted to both lateral guidance and central guidance depending on the toothed pulleys. The present invention also aims to provide a toothed belt mechanical junction designed to respect the regular pitch between the teeth and thus ensure a perfect meshing with the gears, in a wide range of steps, for example from 8M to 32M and in a wide range belt widths, for example from 12mm to 25mm, thus making it possible to cover all applications of the cycle to the industry, simply by adapting its mechanical joint. For this purpose, the invention relates to a power transmission belt of the kind indicated in the preamble, characterized in that the strands of the turns or longitudinal loops of said at least one tensile cable forming said tensile core are all arranged side by side. in the same plane, without being superimposed, this plane coinciding with a median plane of the belt corresponding to its neutral fiber, in that the axis of said at least one transverse orifice or of said at least one locking rod of each of said ends is also positioned in said median plane of the belt corresponding to its neutral fiber, and in that said at least one junction device is arranged to separate the teeth of said ends of said regular pitch or a multiple of said regular pitch.

In a first embodiment, said at least one joining device may comprise at least one connecting link provided with two eyelets with parallel axes, spaced from said regular pitch, and at least one removable locking rod, and said at least one strip section may comprise at least one transverse orifice in at least one of said ends to accommodate said at least one removable locking rod. In this case, one of the sides of said at least one connecting link may be secured to one end of said band section by a fixed locking rod. Said at least one junction device may also comprise two removable locking rods, and said at least one tape section may then comprise a transverse orifice in each of said ends to accommodate said removable locking rods. In some embodiments, the two removable locking rods may be integral with one of the connecting links.

Said connecting device may according to the variants comprise two outer link links, arranged on either side of the sides of said strip section and aligned with each other transversely. In this case, the flanks of said strip section may comprise a clearance for accommodating said outer link links in the width of said section.

In a preferred embodiment of the invention, said junction device may comprise at least one internal link link disposed in the width of said band section, and said at least one band section may in this case comprise in said ends. at least one notch for receiving said at least one inner link link. Of course, it may comprise a number N of internal connecting links, and said at least one strip section may comprise in said ends a number N of notches for receiving said inner link links.

In another embodiment, said at least one junction device may comprise at least two junction pieces arranged to be assembled together by a single removable locking rod, and in this case one side of said junction pieces can be fixed. in each end of said strip section), said connecting device being arranged to move the teeth of said ends a multiple of said regular pitch.

As a variant, said at least one joining device may comprise at least one open claw link and two fixed locking rods, said at least one link to claw being provided with two eyelets parallel axes, spaced from said regular pitch, each eyelet being open on a slot opening. In this case, each locking rod can be secured to one end of said strip section. It may also comprise at least one partially open claw link and two fixed locking rods, said at least one claw link being provided with two eyelets of parallel axes, spaced from said regular pitch, one eyelet of which is closed and one eyelet is open on an open slot. In this case, one of the locking rods can be secured to one end of said strip section and pass through the closed eyelet of said at least one claw link, and the other locking rod can be secured to the other of said ends.

Said at least one strip section may then comprise at least one notch in said ends to receive said at least one claw link.

The belt according to the invention may also comprise several strip sections and several junction devices arranged to assemble the corresponding ends of said adjacent strip sections. Brief description of the drawings:

The present invention and its advantages will appear better in the following description of an embodiment given by way of non-limiting example, with reference to the appended drawings, in which:

- Figure 1 is a perspective view of a power transmission belt according to a first embodiment of the invention, intended more particularly in the field of industry, assembled around two toothed pulleys with a first device of junction,

FIG. 2 is a view similar to FIG. 1 of a belt according to a second variant embodiment of the invention, intended more particularly for the field of cycle, assembled around two toothed pulleys by means of a second connecting device,

FIGS. 3 and 4 are enlarged perspective views of the detail A of FIG. 2 showing the junction zone of the belt in which its two ends are joined by the second junction device, respectively in plan view and in bottom view. ,

FIG. 5 is a longitudinal sectional view of the junction zone of the belt of FIG. 3, and FIG. 5A is an enlarged view of detail B of FIG. 5, FIG. 6 is a top view in transparency of FIG. open belt showing the pull core, and Figs. 6A and 6B are enlarged views of details C and D of Fig. 6,

FIG. 7 is a top view in transparency of the junction zone of the closed belt of FIG. 6,

FIG. 8 is a view similar to FIG. 7 of part of the junction zone of the closed belt of FIG. 1,

FIGS. 9 and 10 are front views of a joining zone of a belt according to two embodiments of the invention, shown in tensioned position, in which the notched profile of the belt is not deformed and the pitch P is respected, Figure 11 is a perspective view of a power transmission belt according to a third embodiment of the invention for the vehicle for example, assembled around two toothed pulleys flanges with a third junction device,

FIG. 12 is a bottom view, enlarged and in perspective, of the junction zone of the belt of FIG. 11,

FIGS. 13A and 13B are perspective views of a claw link forming part of the third connecting device, respectively according to two embodiments,

FIG. 14 is a longitudinal and enlarged sectional view of the junction zone of the belt of FIG. 11 provided with the claw link of FIG. 13A; FIG. 15 is a top view in transparency and enlarged of one end of the open belt of FIG. 11 showing the traction core with the claw links of FIG. 13A,

FIG. 16 is an exploded perspective view of a section of the wide belt of FIG. 1 intended more particularly for the field of industry, and

Figure 17 is an exploded perspective view of a section of the narrow belt of Figure 2 according to another embodiment of the invention intended more particularly to the field of the cycle. Illustrations of the invention and different ways of making it:

In the exemplary embodiments illustrated, the elements or identical parts bear the same reference numbers. Referring to the figures, the power transmission belt according to the invention is an open toothed belt provided with a mechanical connecting device for opening and closing said belt. The junction device is made in such a way that, during the tensioning of the belt, no deformation modifies neither the notched profile of the belt, nor the pitch between the teeth to ensure its meshing with toothed gears, pulleys toothed or toothed pulleys of a mechanical transmission, referred to by a generic term "pulley" without this term being limiting. FIGS. 1, 2, 11, 16 and 17 illustrate various alternative embodiments of such an open transmission belt 10, 100, 110, 120, hereinafter referred to as a "belt", closed in a loop by at least one joining device. 40, 50, 60 and geared around two pulleys 1, 2; 1 ', 2' of a mechanical transmission, which may belong to a vehicle, such as a two-wheeled vehicle, a machine, or any device requiring a power transmission between two rotating members. The invention is of course not limited to this type of application, but extends to all types of vehicles, machines, machines, tools, equipment, etc. in all types of domestic, craft applications, industrial, etc. requiring a power transmission belt, a conveyor belt or the like. The principle of the invention is to design an identical transmission belt over a range of dimensions and corresponding transmission forces corresponding to said dimensions, in a step ranging from 8M to 32M, over a bandwidth of 12mm to 25mm, with at least one mechanical junction adapted to the space available for the application in question. These values are given for information only and are not limiting.

Pulleys 1, 2; 1 ', 2' comprise in a known manner a toothed profile formed by a succession of teeth 3 separated by a regular pitch P, and delimiting between them notches 4. The pulleys 1, 2 of Figure 2 further comprise a central rib 5, which is projecting in the notches 4 for transversely guiding the belt 10. This type of central guidance is known by the English name "center track" or "central track" in the specific area of the cycle. Of course, the transverse guidance of the belt 10 is not limited to this embodiment, but extends to any other guide mode, such as lateral guidance by flanged pulleys (see FIGS. 1 and 11). . Any other means of transverse guidance made by other means, but also the absence of guidance may be appropriate depending on the application considered. The embodiment illustrated in FIGS. 1 and 11 illustrates a lateral guiding of the belt 100, 110 by pulleys 1 ', 2' provided for this purpose with lateral flanges 6. Of course, it is possible to combine the two types of belt. central and lateral guidance.

The belt 10, 100, 110, 120 shown comprises in known manner a smooth face 11 and a notched face 12 formed by a succession of notches 13 separated by a regular pitch P corresponding to that of the pulleys 1, 2; 1 ', 2', and delimiting between them teeth 14. Of course, the notched profile of the belt 10, 100, 110, 120 is designed to perfectly match the tooth profile pulleys 1, 2; 1 ', 2' to ensure a meshing without slipping. With reference to FIGS. 2 to 5, the belt 10 further comprises a central groove 15, which is hollowed out in the teeth 14 and which is complementary to the central rib 5 pulleys 1, 2 for its central guidance. This central rib is absent in the belts 100, 110, 120 of Figures 1, 11, 17 since they can be guided by the side flanges 6 of the pulleys, 2 '.

According to the method of the invention, the belt 10, 100, 110, 120 is made from at least one section 16 of a strip of material, hereinafter called "strip section 16". This strip section 16 is open (FIG 6) and made of a synthetic material, thermoplastic or thermosetting, such as a polyurethane (PU), a polyurethane compound, a natural or synthetic rubber type neoprene®, or any equivalent material which has similar properties, namely in particular lightness, flexibility, robustness, high resistance to fatigue. The strip portion 16 may be partially or completely covered with a coating that can help reduce the coefficient of friction, reduce abrasion, and reduce noise, while increasing the life of the belt. This coating may be a reinforcing textile or the like. This strip section 16 may be manufactured by extrusion in the form of a strip of continuous material, cut to the desired width and / or length (s), or by molding, injection, or thermoforming to the width and / or to the desired length (s). Of course, any other equivalent manufacturing technique may be suitable. It is terminated by two ends 17, 18. These two ends 17, 18 are straight and perpendicular to the longitudinal axis of said strip section 16, with or without notch 21 as explained below, depending on the type of mechanical connection chosen. These two ends 17, 18 each further comprise a tooth 14 making it possible to have a sufficient thickness of material to provide a connection with at least one joining device 40, 50, 60. Indeed, the two ends 17, 18 of said strip section 16 are provided to be assembled by a junction device 40, 50, 60 arranged to be at least partly removable. Of course, if the belt 10, 100, 110, 120 is made from several strip sections 16, it will be necessary to provide several connecting devices 40, 50, 60 to assemble the sections together, at least a number N of devices of junction 40, 50, 60 equal to the number N of tape sections 16. The junction device 40, 50, 60 is designed and dimensioned to ensure a spacing of the teeth 14 provided at both ends 17, 18 of the regular pitch P or a multiple a regular pitch P, to ensure the gearing of the belt 10, 100, 110, 120 with the pulleys 1, 2; 1 ', 2'. It is also designed to be removable at least in part to open and close the belt 10, 100, 110, 120 so that it can adopt two states of use: an open state (Fig. 6; 15, 16, 17). ) in which the ends 17, 18 of the strip section 16 are not assembled, and a closed state (Figs 1 to 4; 11 and 12) in which the ends 17, 18 of the strip section 16 are assembled by the device 40, 50, 60. The junction device 40, 50, 60 according to the invention comprises, according to the embodiments, open or closed links, and fixed or removable locking rods, arranged transversely in the ends 17, 18 of the strip section 16. The term "locking rod", a preferably fixed or removable metal axis, of cylindrical or non-cylindrical section, with a smooth, threaded, or notched surface, with or without a head, in one piece or in two parts mounted upside down, these examples not being as limiting.

For this purpose, during the production of the strip section 16 and with reference to the examples shown, in the teeth 14 provided at the ends 17, 18, transverse passages or orifices 19, which cross the width of the strip section 16, are arranged. partially to accommodate the locking pin or rods 42 belonging to the connecting devices 40, 60 of Figures 1 to 8 and 17, or the locking rod or rods 52 belonging to the connecting device 50 of Figures 11 to 16 is integrated for example by an overmolding process.

In the examples represented in FIGS. 1 to 8, the first junction device 40 comprises one or more connecting links 41, each link being closed and provided with two eyelets 43 having a parallel axis and a center distance preferably equal to the pitch P. connecting links 41 are arranged parallel, in the width of said strip section 16 and are connected to the ends 17, 18 by rods of locking 42, which pass through the eyelets 43 and the transverse orifices 19 aligned with each other. At least one of these locking rods 42 is removable and removable to allow disassembly of the connecting device 40 with respect to at least one of the ends 17, 18 and the opening of the strip section 16. The locking rods 42 may well All or some of the parts may be replaced by any other technically equivalent locking member, allowing assembly of the connecting links 41 at the ends 17, 18 of the strip section 16 by interlocking, screwing, crimping, stitching, overmoulding, bonding, welding, or any other known mechanical process. The junction device 40 can also combine different locking members, the essential being that it is removable at least on one side of the connecting links 4L

The variant embodiments illustrated in FIGS. 1 and 2 show that the junction device 40 may comprise several connecting links 41, it being specified that the number of these links and their arrangement in the width of the strip section 16 are not limiting. and are determined according to the width of the belt and the forces to be transmitted by said belt.

The junction device 40 illustrated in FIG. 1 is adapted to a wide belt 110 intended in particular for the field of industry, and comprises a plurality of connecting links 41, and for example thirteen, all housed inside the belt. 110, in notches 21 provided in the two ends 17, 18. All the connecting links 41 are assembled by two locking rods 42 at the ends 17, 18 adjacent to the belt 110. The junction device 40 illustrated in FIGS. 4 is adapted to a narrow belt 10 especially for the cycle domain, and comprises three connecting links 41, including two outer links clad on the sidewalls of the belt 20 and an inner link, having a central position and being housed in a notch 21, the three connecting links 41 are assembled to the ends 17, 18 of the adjoining belt 20 by two locking rods 42. Several link links 41 interiors may well It is understood that the width of the belt is used in order to optimize the mechanical strength with respect to the diameter of the locking rods 42. The arrangement of the two link links 41 outside the strip section 16 imposes a central guide of the belt. belt 10 as shown in Figure 2. Of course, the outer link links 41 can be embedded in the width of the strip section 16, as well as the inner links, thus allowing lateral guidance of the belt by pulleys to flanges G, 2 ', as in Figure 17. In the examples of Figures 1 to 8, the connecting links 41 consist of a metal bar, forming two ears, each provided with an eyelet 43, connected by a part central narrowed. The connecting links 41 shown in more detail in FIGS. 5 and 5A are symmetrical with respect to the vertical median axis and asymmetrical with respect to the horizontal median axis passing through the center of the eyelets 43 with reference to FIG. 5A. substantially shaped glasses, and have a straight outer edge and a hollow inner edge to provide a clearance J both with the top of the teeth 3 with the top of the central rib 5 provided on the pulleys 1, 2 allowing avoid any interference or collision. The term "outer edge", the edge of the links disposed on the side of the smooth face 11 of the belt 10, 110, and "inner edge", the edge of the links disposed on the side of the notched face 12 of the belt 10 110. Of course, the shape of the connecting links 41 is not limited to these variants but extends to any other form compatible with the toothed belt and the toothed pulleys. Two other examples are illustrated and described with reference to FIGS. 11 and 17. Standard commercially available connecting links can also be used, provided that the shape and dimensions of the locking rods 42, 52 and the transverse holes are adapted. 19 who receive them.

In a variant not shown, the junction device may comprise at least two connecting pieces, equivalent or not to links, intended to be assembled together by a single removable locking rod or by any other technically equivalent locking member to make the junction device removable. In this case, each junction piece is connected to one of the two ends 17, 18 of the band section 16, for example by overmolding, crimping, gluing, welding, etc. They comprise at least one eyelet or a transverse passage to accommodate the single removable locking rod which connects them. In this variant embodiment, the junction device is dimensioned to correspond exactly to a multiple of the regular pitch P, for example to 2xP, if it comprises two junction pieces, in order to guarantee the meshing of the toothed belt in the pulleys. toothed.

In the examples of FIGS. 11 to 15, the second junction device 50 comprises open links, called claw links 51, 5G, which are illustrated in detail in FIGS. 13A and 13B, which have the advantage of being able to be assembled and dismounted on locking rods 52 fixed and non-removable, which does not prevent the use with removable locking rods 52. These claw links 51, 5G are preferably assembled at the ends 17, 18 of the strip of material 16, from below or the notched face 12 of the belt 100. They can also be assembled by the top or the smooth face 11 of the belt 100, but this solution is not optimal taking into account in particular the shape of the belt 100, the little material available in the upper part of the belt 100, the way the belt 100 works in bending and in traction, etc. In this embodiment, the locking rods 52 are advantageously secured to the ends 17, 18 of the belt 100, and preferably overmolded to be embedded in the material web 16. Thus, they are no longer removable, as in the device 40, where it was necessary to thread them through the eyelets 43 and the transverse orifices 19. In this embodiment, it is preferable to use locking rods 52 provided at least partially with a notch or the like to promote the mechanical fastening of the material strip material 16 in the overmolded areas of the locking rods 52. In the example shown in Figures 11, 12 and 15, all the claw links 51, 5G are housed within the width of the belt 100 and more precisely in notches 21 provided for this purpose in the ends 17 and 18 of the strip of material 16. This type of assembly allows on the one hand to ensure that they do not accidentally exit the locking rods 52 from the sides of the belt 100, and secondly to prohibit any contact with the lateral flanges 6 of the flange pulleys G, 2 'according to FIG. 11. In addition, the claw links 51, 5G being housed symmetrically with respect to the longitudinal axis of the belt 100, they do not interfere with the central rib 5 pulleys 1, 2 in the event of a central guide according to Figures 1 and 2. In the example shown in Figures 11, 12 and 15, the junction device 50 comprises two claw links 51, 5G. The number of claw links 51, 51 'is of course not limiting and may be equal to one or greater than two, this number may be even or odd, depending on the transverse dimension of the belt 100. If the number claw links 51, 51 'is an odd number, so a central guide of the belt 100 will no longer be suitable (see Figs 1 and 16).

Figures 13A and 13B illustrate two examples of claw links 51, 51 'compatible. In the first example, the claw link 51 according to Figure 13A consists of a metal bar, forming two ears, connected by a narrowed central portion. Each ear has an eyelet 53 open on a slot 54 opening into the upper edge of the claw link 51, the two open eyes 53 having parallel axes and a spacing preferably equal to the pitch P. The slots 54 are also slightly inclined. one towards the other, along an axis A with respect to the vertical axis with reference to FIG. 14, so that their axes A intersect beyond the upper edge of the claw link 51. Thus, the slots 54 delimit with the corresponding end of the ears, a kind of claw 55 promoting an automatic locking of the claw link 51, when it is fitted on the locking rods 52, and avoiding any accidental release of the claw link 51. The locking is also obtained thanks to the tension exerted on the belt which blocks the claw link 51 by means of the claws 55. The claw link 51 is symmetrical relative to its vertical median axis and asymmetrical with respect to a horizontal median axis passing through. by the center of the eyelets 53 with reference to Figure 14. It has substantially a shape of glasses, and has a straight outer edge and a hollow inner edge to provide a clearance J with the top of the teeth 3 provided on the pulleys G, 2 thus avoiding any interference or collision.

In the second example, the claw link 51 'according to FIG. 13B differs from the first example in that it has in one of the ears a closed eyelet 53', and in the other ear an eyelet 53 open on a slot 54 delimiting a claw 55. This embodiment, associated with fixed locking rods 52, makes it necessary to integrate, in one of the ends 17, 18 of the strip of material 16, the side of the claw link 51 'comprising the eye 53 'closed, traversed by one of the locking rods 52, to bind the corresponding side of the claw link 51' at the end

17 or 18 of the strip of material 16. Of course, the shape of the claw links 51, 51 'is not limited to these embodiments, but extends to any other form compatible with the toothed belt and pulleys toothed. Figure 16 is a partial enlarged view of the connecting device 40 of Figure 1 adapted for a belt 110 said wide relative to the other belts 10, 100 120, intended in particular in the field of industry. This junction device 40 comprises a plurality of connecting links 41, in the example represented thirteen links, distributed at regular intervals in the width of the belt 110. The connecting links 41 are all housed inside the belt 110. in notches 21 provided for this purpose in the ends 17 and 18 of the strip of material 16. To facilitate the opening and closing operations of the belt 110, all the connecting links 41 are connected by one of their sides at one end 17 of the strip of material 16, via a locking pin 42 fixed. Another locking rod 42, which is removable, allows in a single operation to mechanically link the free side of the connecting links 41 at the other end 18 of the strip of material 16 after having fitted them into the corresponding notches 21. Of course, it is also possible to use a junction device 50. In this case, the two locking rods 52 are secured to the ends 17 and 18 of the strip of material 16 in order to fit the claw links 51 by fitting therein. , 5 G with reference to Figures 11 to 15. If one opts for 5G open claw links, in part, they can be secured in one end 17, 18 of the belt 110 and no junction piece can be lost. FIG. 17 illustrates another example of a so-called narrow belt 120, intended in particular for the cycle domain, closed by a third junction device 60. This junction device 60 comprises three connecting links 61, 61 ', including two links 61 which can similar to the links 41, and a link 61 'which forms a locking link since it comprises in an integrated manner two locking rods 62. In addition, the flanks of the material strip 16 comprise a clearance 121 at the right of the zone. connecting junction to accommodate two link links 61, 61 'outside the width of the belt 120, and an inner link link 61 in the corresponding notches 21. The assembly of the ends 17 and 18 of the strip of material 16 to close the belt 120 is fast since the establishment of the third connecting link 61 'makes it possible to bind and lock the two other links 61 to said ends 17, 18 thanks to the integrated locking rods 62. Of course, the number of connecting links 61, 61 'is not limited and may be two or more than three depending on the width of the belt and the forces to be transmitted. Of course, it is possible to use any other type of rapid assembly link such as those used in particular in the field of the cycle.

These various embodiments illustrate a few examples of the diversity of connecting devices that can be used to removably assemble the ends 17 and 18 of a belt 10, 100, 110, 120, being clarified that these examples are not limiting. It is of course possible to combine the various embodiments of the junction devices 40, 50, 60 together in all the belts 10, 100, 110, 120 illustrated. The belt 10, 100, 110, 120 according to the invention is furthermore reinforced by adding a traction core 22 embedded in the thickness of the strip section 16 and extending longitudinally between the two ends 17, 18 (FIG 6), conferring on said belt 10, 100, 110, 120 increased performance in terms of tensile strength and dimensional stability, properties essential for the transmission of forces without slip. The principle of construction of a tensile core is described in particular in EP 2 949 965 B1. In the example shown in FIGS. 6, 6A and 6B, the traction core 22 consists of a single traction cable. 23, circulating from one end 17 to the other end 18, wound in turns around the transverse orifices 19 or locking rods 42, 52 if they are integrated by gluing, overmoulding or the like, into one and / or other of said ends 17, 18, without these examples being limiting. By "transverse orifices 19" is meant passages for receiving locking rods 42, 52 as well as a side of a connecting link 41, a claw link 51, 51 ', or a piece of integrated junction by gluing, overmolding or the like, in said end 17, 18. In a variant not shown, the tensile core 22 may consist of several traction cables, each wound in an open or closed loop between the two ends 17, 18, around said transverse orifices 19 or locking rods 42, 52. Any other construction of an equivalent tensile core may be suitable. The turns or loops formed by the traction cable or cables 23 may be distributed in the width of the strip section 16 regularly or irregularly as in the belts 10, 100, 110, 120 to take account of the notch 21 or the notches 21. Again, the manner of distributing the turns or loops of the traction cable or cables 23 in the width of the strip section 16 may vary according to the specifications of each belt 10, 100, 110, 120. The fact to assemble the ends 17, 18 of the strip section 16 by connecting links 41, 61, 61 'or links to claw 51, 5 which is reported, optimizes the density of traction cables 23 of the traction core 22 with respect to the connecting device described in the publication EP 2 949 965 B1, and thus provides a level of tensile strength significantly higher than that of the prior art since these cables are no longer cut. In addition, this type of assembly has the advantage of maintaining the integrity of the belt 10, 100, 110, 120 which thus does not include any welding or breaking primer, contrary to the prior art cited.

The traction core 22 is imperatively disposed in the center of the thickness of the strip section 16, more particularly in a median plane of said belt which corresponds to the neutral fiber of the belt 10, 100, 110, 120, just above above the notched face 12 (Figures 9 and 10). The term "neutral fiber" is the median plane in which the length of the fibers is invariable regardless of the radius of curvature of the belt. To achieve this objective, the strands 24 of the turns or longitudinal loops of the traction cable or cables 23 are all arranged side by side in the same plane, without being superimposed, this plane being coincident with said neutral fiber of the belt. Thus, the length of the strands 24 of the traction core 22 is also invariable regardless of the radius of curvature of said belt. The term "traction core 22" means one or more son or cables, individual or assembled twisted or twisted braided or plaited or woven, of textile and / or metal. In a variant not shown, the longitudinal turns of the traction core 22 could be assembled together by a transverse frame forming with them a lattice. This traction core 22 must adhere to the thermoplastic or thermosetting material of the strip section 16 and have excellent tensile strength, high flexibility, minimum elongation or even zero, good resistance to bending. Synthetic continuous filaments will be preferred to metal wires, without this example being limiting. By way of example, mention may be made of the following materials: Kevlar®, carbon, steel and stainless steel fibers, without this list being limiting. Thus, when the strip section 16 is closed in a loop by assembling its ends 17, 18 by means of connecting links 41, 61, 61 'and locking rods 42, 62 removable, or claw links 51, 5 nested on fixed locking rods 52, the loops formed by the traction core 22 around the transverse orifices 19 inside each end 17, 18 are also locked together by the locking rods 42, 52, 62. The result of this original construction is the obtaining of a mechanically very strong junction, in particular in traction in the longitudinal axis of the belt 10, 100, 110, 120, while remaining very flexible in flexion to guarantee a good resistance to fatigue. fatigue and good winding of said belt 10, 100, 110, 120 around the pulleys 1, 2; 1 ', 2', regardless of the diameter of the pulleys.

When tensioning the belt 10, 100, 110, 120 according to the invention, it must not undergo any deformation in its junction zone which could change the pitch P with the consequence of destroying the belt 10, 100, 110, 120 in a few turns since it would not mesh properly pulleys 1, 2; 1 ', 2'. Thus, the position of the transverse orifices 19 or locking rods 42, 52, 62 in the ends 17, 18 of the strip section 16 is decisive, as is the position of the traction core 22. The solution of the invention consists in positioning or aligning the axis of the transverse orifices 19 or locking rods 42, 52, 62 in the same plane as the traction core 22, this plane coinciding with the median plane of the belt which corresponds to the fiber according to FIGS. 9 and 10. Depending on the thickness of the strip of material 16 and the diameter of the locking rods, this positioning may necessitate thickening the strip section 16 to embed the towing cable. 23 wound around the transverse orifices 19 or locking rods 42, 52, 62. Nevertheless, this addition of material has the effect of increasing the weight of the belt and especially its bending stiffness which reduces its radius of curvature. To avoid these disadvantages, the material increase can be advantageously limited to the ends 17, 18 of the strip section 16 by creating a bead 25 above each of the end teeth 14. This extra thickness located on the outer side of the belt 10 is not detrimental to the proper operation of the transmission. Indeed, the smooth face 11 of the belt 10, 100, 110, 120 is generally intended to cooperate with a tensioner roller (not shown), which is subject to a return member to ensure a uniform tension throughout the belt . This tensioner roller thus makes it possible to compensate for any variation in the thickness of the belt, in particular when the junction device 40, 50, 60 and the end beads 25 pass. Note that the outer edge of the links 41, 61 provides continuity between the two beads 25. The smooth face 11 may further comprise or not longitudinal flanges 26 to contribute to the transverse guidance of the belt 100, 110, 120. These longitudinal flanges 26 are visible in FIGS. 3, 4 and 5. Of course, the number of longitudinal flanges 26 may be greater than two depending on the width of the belts 10, 100, 110, 120 and can ensure continuous contact with a tensioner. In an alternative embodiment not shown, these longitudinal flanges 26 could be replaced by close transverse ribs, which would ensure almost continuous contact with a tensioner roller, while limiting the bending stiffness of said belt 10, 100, 110, 120. Possibilities of industrial application:

In the case of a reinforced belt 10, 100, 110, 120, each section of open strip 16 is preferably manufactured by a simple molding process in an imprint which corresponds to the size and profile of the belt 10, 100 , 110, 120 for the application for which it is intended. In a first embodiment, two transverse pins may be placed in the cavity in the two end zones intended to form the ends 17, 18 of said strip section 16, to create the transverse orifices 19, taking care to position the axes of said pins in the median plane of the belt which will correspond to its neutral fiber. The traction core 22 is deposited in the cavity, for example according to the diagram illustrated in FIG. Figure 6, starting from a longitudinal edge of the impression and describing longitudinal turns of a transverse pin to the other transverse pin to reach the other longitudinal edge of the footprint. Thus, turns are formed around the transverse pins which delimit the transverse orifices 19 arranged in the tooth 14 of each end 17, 18. As explained above, any other method of construction of the traction core 22 may be suitable. The traction core 22 thus forms inside the footprint a traction sheet, in which all the strands 24 of the longitudinal turns are situated in the same longitudinal plane, which will be merged with the median plane of the belt corresponding to its neutral fiber. After positioning the tensile core 22, the thermoplastic material is added in the cavity to form the strip section 16 which will form the belt 10, 120. The filled cavity can be placed in a heating press if necessary. To unmold the strip section 16 obtained, the two transverse pins are removed beforehand. When the strip section 16 comes out of manufacture, at least one of its ends 17, 18 can be assembled to the connecting links 41 of the junction device 40 corresponding with a first locking rod 42, the other locking rod 42 being introduced into the eyelets 43 on hold. It can also be assembled to form a belt 10, 120 closed by introducing the two locking rods 42, 62 into the eyelets 43, 63 of the connecting links 41, 61, 61 'and the transverse orifices 19 of the two ends 17, 18 The belt 10, 120 obtained can be stored, transported, etc. either in its open state or in its closed state.

In another variant embodiment according to FIGS. 1 and 16, it is possible to have in the cavity a single transverse pin in one of the two end zones intended to form one of the ends 17, 18 of said strip section 16, to create a transverse orifice 19. Then one side of the connecting link or links 41 corresponding to the junction device 40 can be arranged in the opposite end zone, and a locking rod 42 inserted into the corresponding eyelets 43 of these links, so that the assembly is directly overmoulded with the band section 16 in one of its ends 17, 18. In this embodiment, the device junction 40 will comprise only one removable locking rod 42, allowing its disassembly on the side of the end 17, 18 remained free. The assembly of the two ends 17, 18 to close the belt 10 will thus require only the introduction of this single removable locking rod 42 in the eyelets 43 and waiting in the transverse hole 19 of said end 17, 18 free.

With reference to the non-illustrated variant in which the joining device may comprise at least two connecting pieces, assembled together by a single removable locking rod, it is possible to dispose in each end zone of the impression, a side d a connecting piece so that it is directly overmolded with the corresponding end 17, 18 of the band section 16. In this embodiment, the assembly of the two ends 17, 18 to close the belt will require the introduction of a single locking rod 42 removable in the eyelets or corresponding transverse passages of said connecting pieces.

In the variant embodiment shown in FIGS. 11 to 15, and depending on the type of claw links 51, 51 'that it is desired to use, two locking rods 52 can be placed in the cavity in the two end zones. intended to form the ends 17, 18 of the strip section 16, to overmold them in the two ends 17, 18 of the strip section 16. It is also possible to have in the cavity a single locking rod 52 in one of the two end zones intended to form one of the ends 17, 18 of the band section 16, and have in the opposite end zone, a locking rod 52 through the closed eyelet 53 'of the claw link 51', to overmold them in the corresponding end 17, 18 of the band section 16. In this embodiment, the junction device 50 no longer comprises a removable locking rod 52, but only removable claw links 51 or links claw 51 'hinged, allowing disassembly or both sides, either the side of the end 17, 18 remaining free. Assembling the two ends 17, 18 to close the belt 100 thus will be faster and easier since it will be obtained by interlocking one or both claws 55 of the links 51, 5 on one or two fixed locking rods 52. It is clear from the description that the invention achieves the goals set, namely a new generation of toothed belt mechanical junction, which has the advantage of having two positions of use: an open position greatly facilitating its assembly and its disassembly on any type of frame or frame, whether open or closed, and a closed position offering the same advantages and mechanical performance as the known belts, especially in terms of respect for the regular pitch P between the teeth, tensile strength without elongation, resistance to fatigue.

Notably and thanks to the elimination of the welds with reference to the state of the art described in the publication EP 2 949 965 B1, to the increase in the number of traction cables 23 and the better respect of the pitch P, the belt according to the invention allows the transmission of high forces on the order of 1500N in continuous and 2000N in peak of efforts in the field of the cycle, with narrow belts typically of the order l2mm, whereas comparatively the solution of the state of the art would have achieved a value of effort of 900N. Again, these values are given by way of non-limiting example to demonstrate the new performance of the invention.

The invention therefore opens up new possibilities of applications. One of the applications concerns for example the maintenance of machines. The belt 10, 100, 110, 120 according to the invention can easily comprise one or more strip sections 16, assembled to one another by one or more junction devices 40, 50, 60 in the manner of a chain. It is therefore possible, from different lengths of strip sections 16, to reconstruct several lengths of power transmission belt. This possibility offers machine operators having in stock different lengths of tape sections 16 and different junction devices 40, 50, 60 enabling them to instantly replace a defective belt in order to minimize the downtime of the machine. The present invention is of course not limited to the embodiments described but extends to any modification and variation obvious to a person skilled in the art. In particular, the different embodiments of belt and junction devices can be combined.

Claims

claims

1. Power transmission belt (10, 100, 110, 120) having on at least one of its faces, teeth (14) separated by a regular pitch (P) to form at least one notched face (12). ) arranged to mesh toothed pulleys (1, 2) of a mechanical transmission, said belt (10, 100, 110, 120) having at least one strip section (16) provided with said at least one notched face and a traction core (22) embedded in its thickness to obtain a reinforced belt (10, 100, 110, 120), said strip section (16) being delimited by two ends (17, 18) each provided with a tooth ( 14), and at least one transverse orifice (19) passing through and / or at least one transverse locking rod (42, 52, 62), the ends (17, 18) of said at least one strip section ( 16) being assembled by means of at least one connecting device (40, 50, 60) cooperating with at least one locking pin (42, 52, 62) to be at least partially disassembled able, said at least one connecting device being arranged to form a belt (10, 100, 110, 120) having two states of use: an open state in which the ends (17, 18) of said strip section (16) are not assembled, and a closed state in which the ends (17, 18) of said strip section (16) are joined by said at least one joining device (40, 50, 60), and said pulling core (22). ) comprising at least one traction cable (23) wound in turns or in longitudinal loops between the two ends (17, 18) of said strip section (16) at least partially surrounding said at least one transverse orifice (19) or said at least one corresponding locking rod (42, 52), characterized in that the strands (24) of the turns or longitudinal loops of said at least one pulling cable (23) forming said pulling core (22) are all arranged side by side side by side in the same plane, without overlapping, this plan t coincides with a median plane of the belt (10,, 110, 120) corresponding to its neutral fiber, in that the axis of said at least one transverse orifice (19) or of said at least one locking rod (42, 52, 62) of each of said ends (17, 18) is also positioned in said median plane of the belt (10, 100, 110, 120) corresponding to its neutral fiber, and in that said at least one junction device (40, 50, 60) is arranged to move the teeth (14) away from said ends (17, 18) of said regular pitch (P) or a multiple of said regular pitch (P).

2. Belt according to claim 1, characterized in that said at least one junction device (40, 50, 60) comprises at least one connecting link (41, 51, 5G, 61) provided with two eyelets (43, 53 , 53 ') of parallel axes, spaced apart from said regular pitch (P), and at least one detachable locking rod (42, 52, 62), and in that said at least one strip section (16) comprises at least a transverse orifice (19) in at least one of said ends (17, 18) for receiving said at least one detachable locking rod (42, 52, 62).

3. Belt according to claim 2, characterized in that one of the sides of said at least one connecting link (41, 51, 5G) is secured to one end (17, 18) of said strip section (16) by a locking rod (42, 52) fixed.

4. Belt according to claim 2, characterized in that said at least one junction device (40, 50, 60) comprises two removable locking rods (42, 52, 62), and in that said at least one section of strip (16) has a transverse orifice (19) in each of said ends (17, 18) for accommodating said removable locking rods (42, 52, 62).

5. Belt according to claim 4, characterized in that the two removable locking rods (62) are integral with a connecting link (6G).

6. Belt according to any one of claims 2 to 5, characterized in that said connecting device (40, 60) comprises two connecting links (41, 61, 6G) external, arranged on either side of the flanks said strip section (16), and aligned with each other transversely.

7. Belt according to claim 6, characterized in that the flanks of said strip section (16) comprise a recess (121) for housing said connecting links (41, 61, 61 ') external in the width of said section.

8. Belt according to any one of claims 2 to 7, characterized in that said connecting device (40, 50, 60) comprises at least one connecting link (41, 51, 5, 61) inside, arranged in the width of said band section (16), and in that said at least one band section (16) has in said ends (17, 18) at least one notch (21) for receiving said at least one connecting link (41). 51, 51 ', 61).

9. Belt according to claim 8, characterized in that said junction device (40, 50, 60) comprises a number N of internal connecting links (41, 51, 5, 61), and in that said at least one strip section (16) has in said ends (17, 18) a number N of notches (21) for receiving said connecting links (41, 51, 51 ', 61) interiors.

10. Belt according to claim 1, characterized in that said at least one junction device comprises at least two junction pieces arranged to be assembled together by a single removable locking rod, and in that one side of said parts. in each end (17, 18) of said strip section (16), said connecting device being arranged to move the teeth (14) of said ends (17, 18) by a multiple of said regular pitch (P). .

11. Belt according to claim 1, characterized in that said at least one junction device (50) comprises at least one claw link (51) open and two locking rods (52) fixed, said at least one claw link (51) being provided with two eyelets (53) of parallel axes, spaced from said regular pitch (P), each eyelet (53) being open on a slot (54) opening, and in that each rod of locking (52) is secured to one end (17, 18) of said strip section (16).

12. Belt according to claim 1, characterized in that said at least one junction device (50) comprises at least one claw link (5) partially open and two locking rods (52) fixed, said at least one link with claws (5) being provided with two eyelets (53, 53 ') of parallel axes, spaced from said regular pitch (P), one eyelet (53') of which is closed and one eyelet (53) is open on a slot ( 54) and that one of the locking rods (52) is integral with one end (17, 18) of said strip section (16) and passes through the closed eyelet (53 ') of said at least one claw link (5G), and the other locking rod (52) is integral with the other of said ends (17, 18).

13. Belt according to any one of claims 11 and 12, characterized in that said at least one strip section (16) comprises at least one notch (21) in said ends (17, 18) for receiving said at least one claw link (51, 51 ').

14. Belt according to any one of the preceding claims, characterized in that it comprises a plurality of strip sections (16) and several junction devices (40, 50, 60) arranged to assemble the corresponding ends (17, 18) of said adjacent strip sections (16).