FR2631420A1 - Variable-diameter pulley for variable speed drive - has belt bearing segments engaged in flanges with leaf spring and pin fixing - Google Patents

Abstract

The driving and driven s are equipped with side flanges (108, 109) which slide axially along the shaft (100) in order to increase/decrease the effective diameter. Each flange is connected by a number of belt-bearing segments (105) which collectively form the hub of the pulley. The ends of the segments (5) are engaged in radial slots (106, 107) in the flanges. The protruding ends (114) of each segment extend into radial grooves (113) of the outer support drums (110, 111). A curved leaf spring (115) fits over the end and is maintained by a pin (117) which maintains the spring in contact with the outer face of the flanges. ADVANTAGE - Leaf spring assembly automatically takes up any play/clearance during the movement of the bearing segments.

Description

DEVICE SUCH AS A MACHINE, FOUIN OF A VARIATOR OF
SPEED OF PULLEY TYPE WITH VARIABLE DIAMETERS,
HIGH EFFICIENCY ESPECIALLY FOR HIGH TORQUES
The present invention relates to a mechanical device such as a machine equipped with a speed variator having excellent efficiency.

 The word "machine" must also be taken in its widest sense because the invention makes it possible, for example, to produce vehicles of all kinds, including motorcycles or heavy goods vehicles. The invention provides, in fact, for the transmission of large powers under a reasonable volume and can be achieved in practice, by opposition to certain known devices which are simple views of the mind taking no account of the requirements of rn - lite, technical and economical.

 Speed variators have been known for a long time which include two pulleys with variable diameter, engaged with a single belt. One of the pulleys is me nante, the other driven. According to the difference in the respective diameters of the two pulleys, the ratio of the different speeds while the speed of the motor which drives the pulley is constant. The variation in the speed of rotation of the driven pulley is therefore obtained only by acting on the diameters of the pulleys. The length of the belt being constant, it is necessary to decrease the diameter of a pulley when the other increases and vice versa.

 To vary the diameters of the pulleys1 each is constituted by means of two frustoconical flanges opposed by their small bases and at least one of which is slidably mounted on a common rotary shaft, the belt having a trapezoidal section of corresponding profile corresponding at the angle between the two flanges.

 This conventional fit is not satisfactory for several reasons, one of which is the very low coefficient of adhesion of the belt (especially for those which operate in oil) which has the effect of making it impossible to transmit high powers without slipping. . In addition, mechanical requirements impose on all important dimensions.

 In practice, therefore, there are practically no devices fitted with satisfactory variators when it is necessary to transmit large powers (trucks, machine tools and the like) or when it is necessary to respect low weights and reduced volumes (motorcycles, small devices).

 We then tried to perfect this classic arrangement, in particular by interposing between the belt and the frustoconical flanges of the transverse elements together constituting a hub. When the diameter is minimal, the elements are contiguous and as one approaches the flanges, the elements progress towards the periphery and move away from each other since their width is invariable while the diameter according to which they split up increases.

 According to a variant of this arrangement, several parallel belts, a chain and other more or less elaborate transmission members are used. The transverse elements may include grooves in which the aligned transmission members extend.

 Of course, the elements must be connected to the flanges and can be guided during their radial movements. For this, radial grooves are provided on the opposite faces of the two flanges, the two ends of each element being engaged in two grooves located opposite.

 A device of this type is described in the document FR-A-1 295 478 which provides that the grooves have a T-section and that each element has a lug of shape corresponding to each of its ends. This arrangement is unusable in practice because it makes no provision for the effects of centrifugal force on the elements. However, the centrifugal force is a fundamental parameter of a device of this type since the pulleys are intended to turn quickly. To increase the diameter of a pulley, the flanges must be brought together and the centrifugal force urges the elements in the direction of their radial spacing towards the periphery of the flanges. On the other hand, to reduce the diameter of a pulley, it is necessary to spread the flanges and the centrifugal force is opposed to the return of the elements towards the center. As it is necessarily necessary to provide clearance between the grooves and the tenons and it produces beatings of such violence that they cause intolerable wear of the studs and ultimately the destruction of the device.

 Note that this document describes an extensible strip 70 which is designed not as a function of centrifugal force but to close off the spaces which exist between the elements when they are spaced apart in order to give a better seat to the belt and to slow down its wear.

Document US-A-4 705 492 is also known, which describes a variable speed drive, the flanges of which are provided with radial grooves of open section, that is to say not in
T. The elements have tenons which are engaged in these grooves with a large clearance, as seen more particularly in FIGS. 2, 7, 9, 20, 21, 22 and 25, so that the beats are here again a major drawback which makes the device unusable.

 This mime document describes means designed to overcome the effects of centrifugal force. These are individual means for each element: piano cord 5, radial springs 30 or means common to all the elastic belt elements 50.

 Furthermore, it is known that the belts engaged on two pulleys to transmit the rotation of the other to one another, ziotically pulleys with variable diameter for producing variable speed drives, undergo slippages which greatly impair the performance of the assembly. . If we have succeeded in manufacturing belts which have a yield of 98, this is a very exceptional performance which cannot be taken as a reference for the construction of any type of variable speed drive, by example.

 It is understood, in particular, that the efficiency of the belt which is acceptable with a variator for mopeds is no longer with a variator for large vehicles: trucks, buses or a fortiori combat tanks.

 In any case, there is a relationship between the coefficient of friction and the tension of the link "(single or multiple chain, flat belt or with trapezoidal section etc.) and the value of its tension.

 In other words, the results obtained in theory by calculation are not always found in practice due to the physical limitation of certain parameters: resistance of materials, manufacturing processes, cost price, operating and troubleshooting requirements , etc.

 This is why we have already thought of improving the contact between the link and the pulleys regardless of the value of the tension. For this, we have imagined various structures providing for an interpenetration of elements specific to the link and elements specific to the pulleys, in order to obtain an effect localized to the arc of a circle according to which the actual physical contact is made between the link and the pulleys.

 This is how document DE-A597.184 is known, which describes a structure comprising a chain which carries relatively complex mechanical members and intended to cooperate with pulleys with a groove of trapezoidal section.

The document US-A-1.997.284 represents an evolution compared to the structure of the previous document in that it is based on an almost identical principle but embodied in an embodiment providing that each pulley has several grooves and that the assembly includes as many chains as there are grooves
Document DE-A-1,005,792 is also known, which describes a structure comprising a multiple chain, the links of which have teeth with trapezoidal section and are separated laterally from one another by spacers. The elements driven by this chain have, of course, as many longitudinal grooves as there are rows of chains.

 The document US-A-4,048,863 describes a structure which is a little different from the previous ones because the structure described does not include pulleys comprising hollow elements which must receive elements in relief, but wheels with a convex section edge which have to be capped. by jumpers with a concave flared section. The flanks of the wheel are coated with a material with a high coefficient of friction.

 As can be seen, the state of the art thus constituted always provides for jamming, blockages, friction between the link and the rotating elements (pulleys or wheels). One thus expects a significant increase in friction from which it should result an increased capacity to transmit significant motor powers, or couples.

 Unfortunately, experience shows that if this beneficial result is acquired at the "entry 'of the chain on the pulley, we lose all the benefit of these constructions at the" exit ", that is to say at the "place where the chain leaves the pulley. This loosening consumes energy to such an extent that it is necessary to evaluate at 15 or 20% the loss of yield which results from it. Some assemblies make it possible to reduce these losses but they are still around 10%.

 The present invention provides a complete solution to these problems and makes it possible to produce a variable speed drive which can actually transmit high powers and which does not present any malfunction opposing its actual implementation.

 To this end, the subject of the invention is a device equipped with a speed variator of the type comprising two pulleys with variable diameter, a driving pulley kinematically connected to a motor and a driven pulley cinema connected to the part of the device in front of eAtre driven, each consisting of two frustoconical flanges with variable spacing, mounted on a common shaft and provided with radial grooves located opposite to guide the ends of movable transverse elements which together constitute a hub for a member of transmission of rotational movement from one pulley to another such as a chain and which are associated with means intended to at least partially compensate for the centrifugal force which develops when the pulleys are in rotation, characterized in that each end of the elements is associated with a backlash mechanism between said end and the corresponding flange.

According to other characteristics of the invention - each backlash mechanism comprises at least
a part whose position must vary depending on the
centrifugal force; - each backlash mechanism includes a spring
sandwiched between one end of an element and the flange
corresponding; - a friction pad is applied against the flange by
the spring maintained in permanent tension by a member
fixed such as a pin, integral with the element; - the distance between the rooms between which the res
sort is interspersed varies from center to periphery
of each flange; - each flange has a conical bearing surface whose angle
at the top is different from that of the flange itself
so that the effect of the spring is variable depending on the use
cementing of the element considered on its radial path; - the angle at the top of the support surface is smaller than
that of the flange proper for the driving pulley and
the angle at the top of the bearing surface is greater than
that of the flange proper for the driven pulley; - each element is associated with two levers which are mounted
pivoting along an axis oriented so that they are
likely to pivot depending on centrifugal force
and one end of which includes a counterweight while
the opposite end is supported on a friction pad
strongly placed against the corresponding flange; - the elements are connected to each other by pieces
made of elastically deformable material.

- the device is equipped with a mechanism intended for
transmission of a rotational movement of an organ
mechanical such as a pulley to another, by means of a link
such as a chain, belt or the like, engaged on the
two mechanical parts in an arc of a corner circle
possibly variable, is of the type according to which the link
and the mechanical parts have parts intended
to be interpenetrated according to the arc of engagement circle,
and is characterized in that at least some of said
parts are susceptible to transverse movements in
view of the mutual pinching of the parts of the link and the parts
mechanical organs, means being provided for acting
selectively only on the parts which are located in
a circular sector with an angle at most equal to that of
the arc of engagement circle on the mechanical organ
corresponding; - the parts susceptible to transverse movements are
those of mechanical parts, lateral parts
transversely movable being associated on the one hand
to the said parts of the mechanical organs and on the other hand to
control means; - the transversely movable side pieces are
levers arranged redially and one end of which
each of them must be in contact with at least one of the
parts of the corresponding mechanical organ while
the other end must eooI, rrr with a mechanism
actuation ;;
the levers have a length greater than the diameter do
the corresponding mechanical organ to go beyond the contour
of the latter and the actuation mechanism is intended to
act by lateral thrust on the protruding fraction of
only levers that are located in the arc area of
engagement circle;
the actuation mechanism is a disc mounted on a
crank pin of axis perpendicular to its plane and which makes a
preferably adjustable angle with the axis of rotation of
the mechanical organ so that the periphery of the disc
compete towards the end of some of the levers; - the disc is kinematically connected to a mechanism
rotational drive at a speed synchronized with
that of the corresponding mechanical organ so that
the end of the levers and the periphery of the disc have
zero relative speed; ;
the disc is mounted mad and is intended to be driven in
rotation by the end of the levers themselves; - the periphery of the disc has a contact bead in
elastic material;
the transversely movable side pieces are
levers arranged between the parts of the mechanical parts
and the active element of an actuation mechanism; - the parts susceptible to transverse movements are
them of the link;
the link includes links linked to each other
by laterally arched leaf springs and
each secured to a shoe with transverse walls
bevelled intended for use in a circular groove
provided on the hub of the mechanical components.

The invention will be better understood by the
detailed description below made with reference to the drawing
Annex. Of course, the description and the drawing are not
given as an indicative and non-limiting example.

 Figure 1 is a schematic sectional view showing a variable speed drive to equip a device according to the invention and showing two pulleys each consisting of two flanges movable along a common axis.

 Figure 2 is a partial schematic view in cross section showing on a half-pulley a first embodiment for the subjection of the elements and the flanges, using a spring.

 FIG. 3 is a schematic profile view partially showing the inner face of a flange in the two extreme positions of the elements, according to the embodiment of FIG. 2.

 FIG. 4 is a partial schematic view in section showing the connection of the elements with a flange, according to the embodiment of FIGS. 2 and 3.

 FIG. 5 is a schematic plan view of a spring used with the embodiment of FIGS. 2 to 4.

Figure 6 is a partial schematic sectional view showing an alternative embodiment for the securing of elements and flanges
FIG. 7 is a schematic plan view of a spring used with the embodiment of FIG. 6.

 Figure 8 is a partial schematic sectional view showing another alternative embodiment for as subjectissement elements and flanges.

 FIG. 9 is a diagrammatic view at the end of the assembly according to the embodiment of FIG. 8.

 Figure 10 is a partial schematic view in cross section showing on a half-pulley an embodiment for balancing the elements according to the centrifugal force by weights located between the flanges.

 Figure 11 is a partial schematic view illustrating a variant of the embodiment of Figure 10, that is to say using weights located between the flanges.

 FIG. 12 is a partial schematic view showing in cross section two elements used with the variant of FIG. 11.

 FIG. 13 is a partial schematic view of an element used with the variant of FIG. 12.

 Figure 14 is a partial schematic view illustrating a variant of the embodiment of Figure 10, that is to say using weights but these are located outside of the flanges.

 Figure 15 is a partial schematic view in cross section showing on a half-pulley an embodiment for balancing the elements according to the centrifugal force by hydraulic means.

 Figure 16 is a schematic profile view illustrating an embodiment providing that all the elements are connected to each other and partially showing the inner face of a flange, the left part of the figure representing the elements in their most away from the center while the right part of the figure represents the elements in their position closest to the center.

 Figure 17 is a diagram for the hydraulic control of the two flanges of the same pulley.

 Figure 18 is a diagram for the hydraulic control of only one of the two flanges of a m & e pul.ie while ensuring perfect straightness of the belt extending from the driving pulley to the driven pulley.

 Figure 19 is a partial schematic view in cross section of a mechanical member of a device according to the invention of the variable diameter pulley type (a single mechanical member, that is to say a pulley, is shown) .

 FIG. 20 is a partial schematic view made in section along the line XX-XX of FIG. 19.

 Figures 21 and 22 are partial schematic views in cross section of a mechanical member of a device according to the invention according to two variants of the embodiment providing a pinching of the link by means of lateral levers.

 FIG. 23 is a partial schematic plan view of a link according to the invention, produced in the form of a chain with three parallel strands and comprising laterally deformable elements, this chain being seen in a rectilinear portion, that is to say - say not engaged on a pulley.

 Figure 24 is a partial schematic view showing the chain of Figure 23 engaged on a pulley.

 Figure 25 is a view similar to that of Figure 23 showing the same chain engaged on a pulley.

 Referring to Figure 1, we see a speed variator comprising two parallel shafts 100 and 200, the first being rotated by a motor of any known type 101 while the second is kinematically connected to a mechanism 201. The variator makes it possible to drive the mechanism 201 at variable speed while the motor 101 rotates at constant speed.

 For this, the shaft 100 carries a pulley 102 called "driving pulley", formed by two tapered flanges 103 and 104 opposite by their small base and mounted sliding to be able to be moved apart and brought together. Symmetrically, the shaft 200 carries a pulley 202 called "driven pulley", formed by two frustoconical flanges 203 and 204 opposed by their small base and mounted sliding so as to be close and apart. A belt 300 transmits the movement from the pulley 102 to the pulley 202 by resting on transverse elements 105 and 205 respectively. Depending on whether the flanges of the pulleys are moved closer or apart, the corresponding elements are more or less close to the center of the pulley and the linear speed being constant, the speed of rotation is minimum for a maximum pulley diameter and maximum for a minimum pulley diameter.

 These known arrangements being recalled, the invention relates to the connection between the elements 105-205 and the corresponding flanges as will now be described.

 It can be seen in FIG. 1, that the flanges 103104 and 203-204 have radial grooves 106-107 and 206-207 which do not open at the periphery of the flanges but, on the contrary, leave a solid part 108-109 ai.

208-209 forming a stop. On the outside of the flanges 103-104 and 203-204, there are holding drums 110-111 and 210211 provided with radial slots 112-113 and 212-213. Each of the elements 105 has one end engaged in a groove 106 and its other end engaged in a groove 107. Symmetrically, each of the elements 205 has one end engaged in a groove 206 and its other end engaged in a groove 207. In addition, each element 105 and each element 205 is subject to the corresponding flange by a member placed against the sides of the grooves located outside the flanges, the slots 112-113 and 212-213 allowing location without annoying contact of the ends of the elements-- 105 and 205 as well as holding members.

 Given that the two pulleys 102 and 202 on the first part, the flanges 103, 104, 203 and 204 on the second part and the elements 105 and 205 on the third part respectively have the name structure, the description which follows refers only to a single pulley, or a single flange or a single element, or even to a single end of an element and it is understood that the indications given individually are in reality valid for all.

 Referring to Figures 2 to 9, there is shown an embodiment according to which the holding members are constituted by springs.

 Figures 2 to 5 are different views of a variant mEmf in which each end of the elements 10.E carries an extension 114 on which is engaged a leaf spring 115 traversed for this purpose by an opening 116 and arched. The extension 114 is traversed by a hole for the passage of a pin 117 which is intended to immobilize the spring leaf 115. We therefore calculate the camber of the spring leaf 115, the position of the pin hole and the diameter of the latter to maintain the leaf spring applied against the outer face of the flanges according to a pressure calculated beforehand.

 In a fairly frustrating version, we could apply the cat 118 and 119 of the spring leaf 115 directly against the corresponding flange but -because of their relative movement, the flanges would suffer very significant wear. This is why it is preferable to interpose a shoe 120 between the flange and the leaf spring. The shoe 120 is also crossed by an opening in order to be able to be engaged over the extension 114.

With this assembly, there is no relative movement between the supporting catches 118 and 119 of the spring leaf 115 and the shoe 120. The latter slides against the external face of the flange when the elements 105 move and the provision may be made to make the shoe 120 of an anti-friction material or to provide a coating of this material, for example polytetrafluoroethylene, to reduce friction and therefore the heating and wear of these moving parts.

 With the arrangements which have just been described, it is understood that each element is subjected elastically to the two flanges of the pulley and that these are biased towards one another. This produces a structure, admittedly flexible but which has impeccable behavior and which does not cause any random beats or movements and parasites detrimental to its proper functioning.

 To further increase the quality of the assembly, provision is made for the side walls 121 and 122 of each groove to be inclined and for the end of the elements 105 to have cutaway walls of the same slope. The embedding of this end in the groove is therefore without play and, even, with automatic play take-up, thanks to the constant action of the spring leaves 115.

 In FIGS. 6 and 7, we see another variant according to which the extension 114 of the elements 105 has two lateral supports 123 and 124 in order to maintain a spring leaf 125 arched in the opposite direction from that of the leaf 115. With these provisions , the blade 125 is pressed directly against the flange but by a smooth surface and not by edges like 118 and 119, which makes it possible to remove the shoe 120 without causing wear of the flange. For this, the leaf spring 125 is traversed by an opening 126 corresponding to the opening 116 and the cutout of which has on the one hand two edges 127 and 128 which must cooperate with the supports 123 and 124 and on the other hand notches 129 intended to avoid breakage of the blade 125 where it is particularly stressed at break.

 Here again we find the "conical" embedding of slopes 121 and 122.

 In FIGS. 8 and 9, we see another variant according to which the flange 104 has a rib for each groove, which amounts to saying that each groove 107 has for each of its longitudinal sides a flange 130 and 131 on the face outside of the flange. These edges 130 and 131 constitute bearing surfaces for an anti-friction pad 132 suitably profiled and held against them by a leaf spring 133 braced on it as has been described with reference to FIGS. 6 and 7.

Here again we find the "conical" embedding
slopes 121 and 122.

In Figure 1, we notice that the face
outer of the flanges has a taper different from that
of their inner face, which gives the grooves a
variable depth from center to periphery. This
disposition has the effect of making the effort variable
elastic exerted by the springs on the flanges since
the spacing between the bearing surface of the elements and the
spring support surface varies.

 This is to achieve an adequacy between this pinching effect and the centrifugal force which itself varies according to the radius at which the elements are located. To simplify the understanding of the drawing, we have deliberately exaggerated the difference in taper.

 The centrifugal force has a maximum value for the driving pulley 102 when the elements 105 are close to the periphery, that is to say when they offer the belt 300 the largest possible diameter. On the contrary, the centrifugal force has a maximum value for the driven pulley 202 when the elements 205 are close to the center, that is to say when they offer the belt 300 the smallest possible diameter.

 This is why, for the driving pulley 102, the angle at the top of the external bearing surface is smaller than the angle at the top of the flange proper, that is to say its internal face. This results in an increase in the pressing force of the ends of the elements 105 from the center towards the periphery or, in other words, a compensation for the centrifugal force since the elements 105 are applied more and more vigorously when the centrifugal force increases.

 In the same way, for the driven pulley 202, the angle at the top of the external bearing surface is greater than the angle at the top of the flange proper, that is to say its internal face. This results in a reduction in the pressing force of the ends of the elements 205 from the center towards the periphery or, in other words, a compensation for the centrifugal force since the elements 20lu) are applied more and more vigorously when the force centrifugal increases.

 The elements 105 and 205 are retained against the centrifugal force by the belt 300 only in the area of the pulleys where this belt is applied against them. In the area where the elements are free1 they must be retained and this is the role of the means of securing to the flanges described above. A person skilled in the art knows how to calculate the forces due to the centrifugal force and to deduce therefrom the plating forces to be provided all along the radial grooves.

 However, it is an additional security to provide the solid parts 108-109 and 208-209 because they constitute stop stops in the event that, by accident, an element 105 or 205 is no longer retained against the flanges, this which could happen if a spring breaks for example.

 Referring to Figures 10 to 14, we see another embodiment of the subjection of the elements to the flanges, modulated according to the centrifugal force, no longer using the effect of springs but that of moving masses also subject with a centrifugal force but developing forces antagonistic to those of the centrifugal force which is exerted on the elements 105.

 Here, the elements 105 are hollow so as to each be able to contain two moving parts 140 and 141 which are identical to each other and of which, therefore, only one will be described since everything explained for one applies to the other with close symmetry.

 Each part comprises a counterweight 142 situated at the end of a lever 143 whose own mass contributes, of course, to the overall mass up to its axis of articulation which is virtual and results from the contact between a hook ch 144 'it carries at its end opposite to that of the counterweight 142 and a pin 145 held in a housing of the extension 114, against an anti-friction pad 146 similar to the pad 120 of Figures 2 and 4.

 When the centrifugal force develops, the levers 143 tend to pivot in the direction of a distancing of the weights 142 from the center towards the periphery (a lifter vemente in the case of FIG. 10) and with a correlative force of the hooks 144 on the pins 145 which support the contact pads 146 against the outer face of the flanges, increasing the plating of the elements 105 all the more as the centrifugal force which urges them increases itself. Conversely, when the centrifugal force decreases, the levers 143 attenuate their pressure force and the plating which is the consequence thereof.

 Therefore, automatic centrifugal force compensation is again obtained here.

 The length of the lever arm B is equal to the distance measured between the center of gravity G and the counterweight assembly 142-arm 143 of the pivot axis, while the length of the support arm b is equal to the distance measured between the pivot axis and the center of thrust of the hook 144 on the pin 145.

 In practice, B equals twenty five to thirty times b, which means that each counterweight 142-arm 143 assembly has a weight twenty five to thirty times less than that of the element 105, which is practically negligible in comparison with l advantageous effect obtained, namely that each set of weights 142-arms 143 balances half of the mass of the element 105.

In FIGS. 11 to 13, another variant is shown according to which the lever 143 acts in the manner of a crowbar, that is to say that under the effect of the centrifugal force applied to the center of gravity parts 140 and 141, the weights 142 tend to move away from the center and, therefore, to rotate the levers
143 anti-clockwise with the representation of figure 11. Sci, the end of the lever
143 opposite the counterweight 142, there is a step 147 whose concavity is opposite the more acute convexity of a flange 148 formed on the extension 114. The linear contact of the concave angle of the step 147 with the convex angle of the rim 148 constitutes a virtual axis of articulation of the lever 143, which is crossed by a key 149 pressed elastically against the anti-friction pad 146 by means of a spring 150.

 Note that the U-shaped section is very open, that is to say with a slight slope, and rests on a part 151 with a corresponding section in order to ensure lateral retention of the sliding assembly (element 105 and its complements) relative to to the fixed assembly (flange 103 and its complements).

 In FIG. 12, an embodiment is seen according to which each element 105 is hollow to contain, inside its outline, the lever 143 and its counterweight 142.

 In cross section, each element 105 is asymmetrical so as to have a convex face with two converging planes 152 and 153, and a concave face with two planes parallel to the preceding ones 154 and 155. For the stiffening of such an element 105, ribs 156 are provided. , 157, 158 and 159. The rib 156 carries a reinforcing strip 156a on which the belt 300 rests. The intermediate ribs 157 and 158 are sufficiently spaced to be able to contain the counterweight 142 and the lever 143 between them and allow their movements without uncomfortable. The width of the ribs as well as the bevel of their free edge are established in such a way that two neighboring elements 105 are placed perfectly one inside the other, as shown in FIG. 12, when they are in the minimum diameter position.

The embedding of the elements 105 provides great rigidity to the hub that they form and in no way interferes with their movement towards the periphery since they move away from each other in rare time as they slide radially.

 In FIG. 14, a variant of the same embodiment is shown as the previous one, that is to say using moving masses subjected to centrifugal force.

 The flanges 103 and 104 are integral with slides 160 and 161 movable along the shaft 10-0 but integral with the latter in rotation. on the slides 160 and 161, links 162 and 163 are articulated along axes 164 and 165 and receive levers 166 and 17 articulated along axes 168 and 169 and carrying weights 170 and 171.

 According to a first variant, the ends of the levers 166 and 167 are provided with toothed sectors 172 and 173 prized with teeth 174 and 175 provided in a plane and integral with the slides 160 and 161.

 According to another variant, the ends of the levers 166 and 167 are free and the teeth in engagement do not have to exist. On the other hand, the levers 166 and 167 are articulated by axes 176 and 177 to arms 178 and 179 secured to the shaft 100, which has been shown diagrammatically but which the skilled person can easily realize in the convenient.

The operation of this structure is as follows
When the flanges 103 and 104 are brought closer to increase the useful diameter of the pulley, the elements 105 move away towards the periphery and the centrifugal force increases. The movement of the flanges 103 and 104 along the shaft 100 causes that of the sliders 160 and 161 to pull, and, as a result, the links 162 and 163 pull on the levers 166 and 167.

 With the first variant, the toothed sectors 172 and 173 being in engagement with the fixed teeth 174 and 175, the levers 166 and 167 are forced to pivot along the axes 168 and 169.

 With the second variant, the fixed arms 178 and 179 retaining the levers 166 and lui7, these are forced to pivot "in parallelogram" both along the axes 168 169 and along the axes 176-177.

 In one case as in the other, the pivoting of the levers 166 and 167 has the effect that the weights 170 and 171 deviate and, for example, pass from their position in solid line * their position in dotted line. Therefore, the weights 170 and 171 approach the center while the elements 105 move away from it, so that the centrifugal effect of the latter is balanced by the centripetal effect of the weights 106 and 171. It is easy it is up to the person skilled in the art to determine the dimensions, the pivot angles and the masses in order to obtain as perfect a balance as possible.

 In Figure 15, there is shown an embodiment according to which the centrifugal force is balanced by means of a pressurized fluid.

 The flanges 103 and 104 are integral with a slide 180 which carries a wall 181 the edge of which is provided with a seal 182 cooperating with the internal face of a watertight bell 183 provided with a seal 184 .

This arrangement determines a room in which there is a liquid A of incompressible type such as those which are used for remote controls: nui omobi brakes for example.

The operation of this structure is as follows
When the pulley is rotating, the liquid A, under the effect of centrifugal force, is localized at the periphery of the chamber determined by the slide 180, the wall 181 and the bell 183, as shown in FIG. 15 When the flanges 103 and 104 are in the maximum spacing position, the distance d which separates the wall 181 from the bell 183 has a maximum value. As the radius r measured between the slide 180 and the outer edge of the bell 183 remains constant, the volume of the chamber is then maximum and the liquid occupies the periphery of the chamber on a fairly small surface of the wall 181 and of the bell 183.

 The effect of the liquid is twofold: by its location n the periphery of the system, it forms a mass strongly subject to centrifugal force; by the small front surface which it occupies, the pressure exerted on the wall 181 and thereby on the slide 180 and on the corresponding flange is low.

 When the flanges 103 and 104 are brought together to increase the useful diameter of the pulley, the slides 180 also move and carry with them the walls 181. The bells 183 being fixed in the axial direction, the distance d decreases and, correlatively , the volume of the room too. The liquid A is then forced to extend over a larger surface of the walls 181 and of the bells 183, from which there results a higher pressure on the walls 181, pressure which is transmitted to the flanges 103 and I 04.

 Therefore, abu as the centrifugal force increases and tends to move aside the flanges 10: 3 and 104, these receive a balancing action due to the liquid A, action which is proportional to the centrifugal force and continues, as the latter.

 Referring to FIG. 16, we see another embodiment of the invention according to which all the elements 105 are connected to each other by pieces of elastic material 185, for example rubber, located closer to the axis as the elements 105 proper.

 Today elastic materials are available which can easily undergo an elongation of more than 400 t without any risk of rupture, this occurring at 700 s or more. A material of this type is chosen here, which ages well and which, if necessary, behaves correctly for operation in oil.

 When the elements 105 are at the smallest diameter (right part of FIG. 16) -, the rubber parts 185 occupy a minimum volume, inside the contour of the hub formed by the elements 105 located against each other.

 When the elements 105 are at the largest diameter (left part of FIG. 16), the rubber parts 185 are at their maximum tension which can be chosen, for safety reasons, below that which they could support (for example 250 t for a material such as that which was mentioned above commonly working at 400 t).

 It is understood that as the centrifugal force increases, the tension of the material also increases and the parts 185 stress the elements 105 towards the center, that is to say in opposition to the effects of the centrifugal force which is thus finds itself perfectly balanced.

 In addition, the permanent natural tendency of the material being to contract, the resultant is indeed radial and centripetal but the initial component of the material is transverse, so that here again there is an automatic catching up of the lateral play of the elements 105 relative to to flanges 103 and 104.

 The sflr operation of a variable speed pulley type variable speed drive requires that the belt 300 always remains parallel to itself. To do this, we will describe two different embodiments which make it possible to achieve this goal, with reference to FIGS.

 In FIG. 17, the two flanges are substantially frustoconical, that is to say of the type already described under the references 103 and 104, and provision is made to move them both simultaneously so that the axis of the belt remains unchanged.

 The flanges 103 and 104 comprise hollow circular drums 400 and 401 closed by plates 402 and 403 provided with O-ring seals 404 and 405 and engaged on the shaft 100 to which they are secured poi star driven in rotation with it.

 Each drum 400-401 and each corresponding tray 402-403 together determine a chamber 406 and 407 respectively for an incompressible liquid B.

 Furthermore, the shaft 100 is pierced with two concentric passages of different diameters 408 and 409, the first receiving a conduit 410 which determines with the passage 409 an annular space which communicates with the chamber 406 by a radial hole 411. The passage 408 communicates with chamber 407 through a radial hole 412.

 The shaft 100 pivots in a fixed housing 413 with the interposition of an O-ring seal 414, this housing 413 comprising two housings 414 and 415 communicating with two radial conduits 416 and 417 connected to pipes 418 and 419.

 These lead to cylinders 420 and 421 formed in a block 422 and receiving sliding pistons 42: 3 and 424 which are paired, that is to say that they are both connected to a single operating part 425 integral with a control rod 426 kinematically connected to a movement mechanism of any known type (not shown).

The operation of the device which has just been described is as follows
Depending on the action that is imparted to the movement mechanism, the control rod moves more or less, in one direction or in the opposite direction and the operating part 425 acts on the two pistons 423 and 424 which, therefore, are rigorously coordinated. The liquid
incompressible which fills, without air or vacuum, all the space of the pipes, passages and chambers, is sucked or discharged.

 The movement of liquid involves exactly the same time and for the same volume the two chambers 406 and 407 so that the flanges 103 and 104 are separated or brought together in a perfectly symmetrical manner. Consequently, the elements 105 which support the belt 300 do not undergo any lateral displacement and always remain in the same axis. So it is the same for the belt since, obviously, the two pulleys 102 and 202 must be designed in the same way. With this structure, the pulleys 102 and 103 change in diameter, one in the direction of a increase and the other in the direction of a correlative decrease, and vice versa according to the speed variation that is desired for the driven pulley, the belt 300 for its part retaining at the fqis a constant tension and an axis of unchanging location.

 Referring now to FIG. 18, we see a variant according to which the belt 300 also retains an invariable location axis although only one of the two flanges is made mobile.

 In this figure, we see that the drive pulley of the variator. The shaft 100 is made integral with a pinion 500 kinematically connected to a motor of any known type (not shown) and carrying a drum 501 whose external face is provided with concavities 502 in which are placed free balls 503 in sufficient number so that they are well distributed around the tree 100.

The flange 103 is wedged on the shaft 100 in a position such that the balls 503 are tangent both to the bottom of the concavities 502 and to the flange 103, as close as possible to the shaft 100 when the rutile diameter of the pulley must be minimum, which is the case shown in FIG. 18.

 Opposite the flange 103, there is a flange 504 wedged on the shaft 100 and carrying guides 505 for the elements 105 but this flange 504, instead of other substantially frustoconical like all those which have been described so far, is plane, that is to say that its face which is opposite the flange 10 is in a virtual plane perpendicular to the axis of the shaft 100. Therefore, the ends of the elements 105 cooperating with the flange 103 , of a type already described, are substantially inclined at the same angle as the angle at the top of the virtual cane generating the useful face of the flange 103, while the opposite ends, cooperating with the flange 504, of a type already described , are substantially orthogonal to be applied effectively against the face of the flange 504.

The operation of the device which has just been described is as follows
Depending on the speed of rotation of the motor, the pinion 500 and the drum 501 are driven at a greater or lesser speed and the balls 503 are subjected to a more or less strong centrifugal force which biases them more or less intensely towards the periphery of the drum 501 and the flange 103. It is observed that the distance measured parallel to the axis 100 which separates the bottom of the concavities 502 and the external face of the flange 103 is maximum near the shaft 10 and minimum, or even practically zero apart from play, at the periphery. Consequently, the further the balls 503 move away from the shaft 100 under the effect of centrifugal force, the more they push the flange 103 towards the flange 504 and this, up to a maximum which corresponds to the limit of approximation of the flanges 103 and 504. (this position is shown in dotted lines in Figure 18).

 The concavities 502 end with a stop 506 which guarantees the blocking of the balls 503 but it is known that the approximation of the flanges is strictly limited by the width of the elements 105 and it is therefore not possible to produce such a separation of the flange 103 and the drum 501 that there appear a space capable of letting the balls 503 escape.

 When the speed of the drum 501 decreases, the centrifugal force also decreases and the balls 503 are biased towards the center as a result of three combined effects first, the centrifugal force which they undergo directly decreases, then the belt 300 supports the elements 105 towards the center (since correspondingly the useful diameter of the other pulley increases), which elements 105 tend to push the flange 103 towards the drum 501 and, finally, the walls in presence (. bottom of the concavities 502 and external fncr of the flange 103 ) thus close together being divergent from the periphery towards the center push the balls 503 towards the center.

 It can be seen that here again the axis of the belt 300 does not change location since the elements 105 slide radially but always parallel to the plane of the flange 504. The drawing clearly shows that the position of the belt 300 at the maximum diameter is exactly perpendicular to its position at minimum diameter.

 This structure is particularly well suited to equipping small machines, in particular for two-wheeled vehicles with a small displacement engine such as the. mopeds.

 For all the examples of the above description, we have retained the case where the transmission is ensured by a belt and we know that modern industry is capable of supplying belts which have an excellent efficiency since it can reach 98 X. Consequently, it is currently possible to produce variable speed drives in accordance with the invention which transmit significant torques since the improvements in mechanical structure according to. the invention are supplemented by the qualities specific to the belts themselves.

 Referring now to Figures 19 and 20, there is shown a mechanical member of a device according to the invention produced in the form of a pulley between the flanges of which a belt is engaged on a hub.

 More precisely still, it is here a variable diameter pulley whose flanges are slidably mounted on a common shaft and are joined by radially movable transverse elements constituting a hub whose diameter increases when the flanges are brought together. on the other while it decreases when the.

flasks are discarded. The belt is engaged on the hubs of two similar pulleys and the diameter of one of the hubs increases when that of the other decreases, this suitably controlled assembly constituting a speed variator of a type known per se.

 But it should be emphasized that the invention is not limited to this kind of mechanism since it applies not only to pulleys but also to rollers and pinions, the following description applying mutatis mutandis to Cf genus of organs, the necessary adaptations being within 1 reach of the skilled person.

 On the shaft 600 are slidably mounted two flanges 601 and 602 whose opposite faces are frustoconical, as is known per se, and comprise radial guides 603 and 604 for transverse elements 605 together constituting a hub on which a belt 506 is engaged party.

 According to the invention, the belt 606 comprises longitudinal ribs 607 which have to penetrate into grooves 608 of the elements 605.

 The ribs 607 constitute parts of the link and the grooves 608 constitute parts of the elements 605, parts of which must interpenetrate in the zone corresponding to the arc of a circle according to which the belt 606 is engaged on the hub of the pulley.

Each 60fi element has three separate parts. A part 610 called "lower" serves as a support for the other two and comprises at its ends organs
(not shown) having to cooperate with the guides 603-604 to ensure the radial sliding of the elements 605 from the center towards the periphery and vice versa depending on the movements printed on the flanges 601 and 602. A rigid and robust part 611, which comprises reliefs 612 which can flex, placed along an edge of the grooves 608 and engaged in housings of the third part 613 in which the grooves 608 are located and which receives the belt 606.

 The three parts 610, 611 and 613 must be joined to one another by any known means opposing their separation when they are no longer applied against one another by the belt 606 but allowing lateral movement reliefs 612. These means are neither shown nor described in detail because they are obviously within the reach of those skilled in the art and are left to their free choice according to the practical mechanical solutions finally retained by him for the materialization of the 'invention.

 Opposite each element 605, there is at least one lever 615 disposed radially on an "internal" face of a flange 601-602.

 Here, each element 605 corresponds to two levers 615 and 616 provided respectively on the flange 601 and on the flange 602.

 The levers 615 and 616 are each held laterally, to keep their orientation, for example thanks to the edges of grooves 617 and 618 in which they are placed but they must be free to pivot transversely, that is to say inclined wander towards each other, their fulcrum respectively 619 and 620 being on the corresponding flange, near the shaft 600.

Consequently, their tilting movement towards each other is done by their most eccentric part.

 We see that by causing this movement, we force the levers 615 and 616 to compress the part 611 of the elements 605, so that the ribs 607 of the belt f '606 are pinched between a fixed edge of the grooves 60R and the reliefs 612 correspondents.

 The constituent materials of the interpenetrated parts, their coefficient of friction and the intensity of the pinching are parameters to be taken into consideration to achieve the goal sought, namely a joining as perfect as possible of the link and hub so that the relative speed between these organs is zero.

But, according to an important characteristic of the invention, the pinching must be as intense at the "entry" of the belt on the pulley as it must be quickly neutralized at the "exit
For this, one can provide, as shown in Figures 19 and 20, two discs 625 and 626 integral with crank pins 627 and 628 whose axes x and y may have variable inclinations relative to the fixed axis of the shaft 600 A mechanism of any known type (not shown) is used to actuate the crankpins 627 and 628 so that their movements are coordinated.

 When the axes x and y of the crank pins 627 and 628 are coincident with the axis of the shaft 600, the disks 62.5 and 626 are in planes perpendicular to these axes and their position is such that they are at a certain distance from the flanges 601 and 602, no contact occurring between the latter and the discs 625 and 626.

 When an inclination of the crankpins 627 and 628 is caused, their axes x and y compete and the periphery of the discs 625 and 626 is placed on the path of the fraction of the levers 615 and 616 which exceeds the outline of the flanges 601 and 602.

 When the discs 625 and 626 are slightly inclined, an arc of a very small angle is intersecting with the geometrical location of the levers 615 and 616 goes in rotation with the flanges 601 and 602. Consequently, only one lever 615-616 at the times will be <) inera when meeting the periphery of the 625-626 discs. It is the lever 615-61 r which the rotation brings opposite the point of the periphery of the disks 625-626 the most salient (upper part of FIG. 19).

 As the inclination of the crankpins 627 and 628, and therefore of the discs 625 and 62 (3, is increased, the arc of circle of these discs located on the path of the levers 615 and 616 increases and the number of levers 615 and 616 which simultaneously meet the discs 625 and 626 increases to a maximum which is a function of the difference between the diameter of the geometrical location of the fractions protruding from the levers 615-616 and the diameter of the discs 625 and 626.

 The presence of the discs 625 and 626 on the path of the levers 615 and 616 has the effect of forcing the latter to tilt and, as explained above, to compress the part 611 of the elements 605.

By properly calculating the diameter of the discs 625 and 626 and their angle of inclination, one obtains precisely the exact number of levers Sîr-sîs inclined necessary to pinch the ribs 607 of the belt 606 in a lower angle A (Figure 20) at the corner
B which measures the arc of engagement circle, that is to say the arc of circle according to which the belt is in contact with the hub of the pulley.

 Consequently, the pinch takes place immediately after the start of the belt-hub contact ("entry") and is eliminated without any energy expenditure, immediately before the end of this contact ("exit").

 To facilitate construction, to avoid rattling noises and. especially the wear of the discs and of the levers, provision is made of beads of elastic material 60 and 631 which cover the periphery of the discs 625 and 626.

 We may wish to drive the crankpins 627 and 628, and therefore the discs 625 and 626, at a speed synchronized to that of the flanges 601 and 602 so that the relative speed of the discs and of the levers is zero.

 However, it is easier to mount the disks 625 and 626 (or the crank pins 627 and 628 which carry them), because the ends of the levers 615 and 616, when they move in rotation, easily drive the disks 625 and 626. Without no energy expenditure, thus obtaining the inclination of the levers 615 and 616 every year having a zero relative speed between their ends and the discs 625 and 626.

 It is understood that a device equipped in accordance with the invention has marked advantages over the devices of the prior art: yield of 100 t compared to the performance of the link chosen since there is practically no more slippage, transmission of high torques, easy adjustments, low wear of moving parts etc.

Referring now to Figures 21 and 22,
we see two variants of the invention implementing the
same embodiment which consists in using
levers outside the elements 605.

 But here we use a magnetic force to move the levers.

 In FIG. 21, it can be seen that the flanges have magnetic bars 700 and 701 which are distributed in a crown on the flanges, face to face and alternately North and South, the bars which are opposite one another in front of Between opposite polarity, as indicated by the letters N (North) and S (South), so that the magnetic field symbolized by the arrows x closes transversely to an endless chain whose links 702 pass between discs 703 secured to the tree d pulley 704.

 The assembly carries pies these 705 provided with slots for the discs 703 and serving as a fulcrum at 706 and 707 for one-piece levers having two branches 708 70 and 710-711.

 It is of course possible to use electromagnets or permanent magnets since the ones are an equivalent of the others, at least for the effect which we want to obtain here, namely a pinching action of the chain immediately after are " entry "on the pulley and release immediately before its" exit ", all without affecting the performance of the device.

 An action on the branches 708 and 710 which are in abutment on the edges 706 and 707, obliges the branches 709 and 711 to pivot and to bear on the levelings 712 and 713, so that they support, by pads 714 and 715, on the extreme discs 703.

 By this system of levers, the magnetic plating becomes a pinch twenty five to thirty times more important. It is therefore possible to have a small number of intermediate disks 703 while ensuring the transmission of an extremely large torque under a reduced bulk.

 FIG. 22 shows the same embodiment comprising lateral levers and a magnetic circuit, but according to a variant concerning the arrangement of the levers. In order to simplify the description, the same references have been kept to designate the mAmsLs elements.

 The magnetic bars 700 and 701 receive individual North and South magnetization. For this, they carry cores 800 and 801 on one side, 802 and 803 on the other for heads 804-805 and 806-807 of electromagnets 808 and 809 with windings shown diagrammatically at 810 and 811.

 Multiplier levers 812 and 813 are articulated according to pivots 814 and 815 on fixed supports 816 and 817, their fulcrum being, as in the case of FIG. 21, the edges 706 and con ;. They are engaged with other levers 818 and 819 bearing on fixed parts 820 and 821 to act by pads 822 and 823 on the end discs 703.

 We can also consider that the levers consist of two branches 812-813 on the one hand and 818-819 on the other hand but in the case of Figure 21 the branchrs are created in a single piece (monoblock levers) while here branches 812-813 and 818-819. are distinct.

The effect obtained is the same as that described and seen in FIG. 21, namely an amplification of the magnetic action providing a pinching of the links 702 of the extremely energetic chain and always at an angle.
A less than the angle of the arc of engagement circle B.

 On the other hand, there is an important difference due to the fact that each magnetic bar 700 and 701 comprises a bipolar magnetization, so that two magnetic fields symbolized by the arrows y and z are closed respectively by the levers 812 of a cat and 813 of l 'other. Consequently, the magnetic field does not pass through the links 702 of the chain. Consequently, one could be satisfied with a unilateral field instead of the bilateral field adopted here when the parameters of size, efficiency and torque allow it.

 As it takes an alternation of North cores and South cores, it is necessary to have a double collector, as is well known in itself.

 The structures that we have just described make it possible to have relatively modest magnetic masses, a light spindle with low inertia and therefore, ultimately, a very efficient assembly.

 Referring now to Figures 23 to 25, we see a different embodiment according to which the parts susceptible to transverse movements are no longer located on the maize hub on the link itself and, here, on a triple chain (three parallel strands).

 Each strand is composed of links 900 joined to each other by spring blades 901 curved laterally. Each link 900 is integral with a shoe 902 whose transverse walls 903 are bevelled, which gives the shoes 902 a wedge shape. We see in Figure 24 that these forms equivalent to a notch and we calculate the slope of the walls 903 so that the pads 902 can be placed against each other when the hub n its minimum diameter, when it is d adjustable diameter type.

 The transverse elements which join the flanges and constitute the hub, have grooves with low clearance, that is to say with a U-section with weakly open branches, in each of which a chain strand penetrates.

 When the chain makes contact with the hub, the links 900 behave like cams, due to the folding of the pads 902 and cause the ends of the spring blades 901 to come together. The latter deviate as shown in diagrammatic in FIG. 25 In reality, they are found in the grooves of the transverse elements constituting the hub and they are braced against the walls of these grooves ensuring an energetic tightening of the pussies on the hub.

 It should be noted that the spacing of the spring blades 701 only occurs when they are stressed by their two ends at the same time. So, when the first shoe 702 comes into contact with the hub, the blades 701 remain normally arched and it is only afterwards, when the next shoe 702 is applied to the hub that the spacing of the blades 701 begins and that the tightening begins.

 Here again, therefore, the tightening begins after the entry of the chains on the hub.

 Symmetrically, the tightening is eliminated before the chains come out since the spring blades 701 regain their normal camber, without tightening against the walls of the grooves, as soon as the first shoe leaves. There is therefore only a negligible effort and very low energy expenditure to neutralize the tightening.

 Naturally, one could choose other solutions making it possible to achieve a structure in accordance with the invention, that is to say comprising moving parts laterally carried by the link and acting in an arc of a circle with an angle less than that of the arc of engagement circle of the link on the hub.

Claims (18)

 1- Device equipped with a speed variator of the type comprising two pulleys with variable diameter, a driving pulley (102) kinematically connected to a motor (101) and a driven pulley (202) kinematically connected to the part (201) of the device to be driven, each consisting of two flanges with variable spacing (103 and 104 203 and 20, mounted on a common shaft (100-200) and provided with radial grooves (106 and 107 - 206 and 207> located opposite) -screw to guide the ends of mobile transverse elements (105 and 205) which together constitute a hub for a member for transmitting rotation movement from one pulley to the other such as a belt (300 or a chain and which are associated with means intended to compensate at least in part for the centrifugal force which develops when the pulleys 102 and 202: are in rotation, characterized in that each end of the elements (105 and 205; is associated with a backlash mechanism (115, 125, 130, 140-14 6- 167, 170- 171, 180-A-181, 185 between said end and the corresponding flange '103-104 and 203-204'  - Device according to claim 1, characterized in that each backlash mechanism comprises at least one part (140-141, 170-171, 181) whose position must vary depending on the centrifugal force.  3- Device according to claim 1, characterized in ~ that each backlash mechanism comprises a spring (115-125-150) interposed between one end (114; of an element (105) and the flange (103-104 corresponding.  4- Device according to claim 3, characterized in that no pad '120, 146 ;, is applied against the flange flO3-104 and 203-204) by the spring (1115-125-150) maintained in permanent tension by a fixed member such as a pin (117-149), integral with the element (105-205).  5- Device according to claim 3, characterized in that the distance between the parts between which the spring (125) is interposed is variable from the center to the periphery of each flange (103-104 and 203-204).  6- Device according to claim 5, characterized in that at least one of the flanges (103-104 and 203-204) is frustoconical and has a conical bearing surface whose angle at the top is different from that of the flange proper so that the effect of the spring (125) is variable depending on the location of the element (105-205; considered on its radial path.  7- Device according to claim 6, characterized in that the angle at the top of the bearing surface is smaller than that of the flange (103-104) proper for the driving pulley (103) and the angle at the top of the bearing surface is larger than that of the flange: 203-204- proper for the driven pulley (202;  8- Device according to claim ', aracé- 15e that each element ::; lG-5 is associated with two levers (143) which are pivotally mounted along an oriented axis so that they are capable of pivoting e function of centrifugal force and one end of which comprises a counterweight (142, while the opposite end is in abutment on a shoe (146) placed against the flange (103-104, corresponding.  9- Device according to claim 1, characterized in that the elements (105) are connected to each other by pieces' 185, of elastically deformable material.  10- Device according to claim 1, characterized in that for at least one of the two pulleys, 102-202 ,, one of the flanges 1O, is substantially frustoconical and the other (504) plane, only the frustoconical flange (103) being movable along the axis common to the two flanges (103 and 504  11- Device equipped with a mechanism according to claim 1, intended for the transmission of a rotational movement of a mechanical member such as a pulley to another, by means of a link such as a chain, belt or the like (606), engaged on the two mechanical members according to an arc of a circle of possibly variable angle, of the type according to which the link (606) and the mechanical members comprise parts (607 and 608) intended to be interpenetrated according to the 'arc of engagement circle, characterized in that at least some of the parts (608) are capable of transverse movements with a view to mutual clamping of the parts (607) of the link (606) and of the parts (608) of the mechanical members, means (625 to 631) being provided for acting selectively on the only parts (608) which are situated in a circular sector with an angle at most equal to that of the arc of a circle of engagement on the corresponding mechanical member.  12- Device according to claim il, characterized in that the parts (608; capable of transverse movements are those of the mechanical organs, lateral parts (615 and 616) movable transversely being associated on the one hand with said parts C608 'of the mechanical organs and on the other hand to control means (szs to 631).  1o- Device according to claim 12, characterized in that the transversely movable lateral parts are levers (615 and 616) arranged radially and one end of each of which must be in contact with at least one of the parts of the 'corresponding mechanical organ while the other end must cooperate with an actuating mechanism.  14- Device according to claim 12, characterized in that the levers (615 and 616? Have a length greater than the diameter of the mechanical member (601-602; ec, corresponding to exceed the outline of the latter ek the mechanism is intended to act by pushing  lateral on the protruding portion of the levers alone (615  and 616) which are located in the area of the arc  of engagement.  15- Device according to claim 14  characterized in that the actuation mechanism is a  disc (625-626) mounted on a pin (697-628) of axis (x-y)  perpendicular to its plane and which makes an angle of  preferably adjustable with the axis of rotation of the organ  mechanical (601-602) so that the periphery of the disc (625-  626; compete towards the end of some of the levers (615 616.  16- Device according to claim 15,  characterized in that the disc (625-626) is connected  kinematically to a rotary drive å  a speed synchronized with that of the mechanical organ  '601-602; matching so that the end of the levers  (615-616) and the periphery of the disc (625-626) have a  zero relative speed.  17- Device according to claim 15,  characterized in that the disc (625-626, 'is mounted loose and  is intended to be driven in rotation by the end of the levers (615-616) eui-memes.  18- Device according to claim 15,  characterized in that the periphery of the disc (625-626;  has a contact bead (630-631) of elastic material  19- Device according to claim 12,  characterized in that the movable side pieces  transversely are levers (708-709 and / 10-, 11, 812  and 813> 818 and 819) arranged between the parts 1703! of  mechanical parts and the active element '700 and, 01; of a  actuation mechanism.  20- Device according to claim 11,  characterized in that the parts (901) liable to  transverse movements are Celts of the link (900-901-902  21- Device according to claim 20, characterized in that 9ue the link comprises links (900) connected to each other by spring blades (901) bent laterally and each secured by a shoe (909, with transverse walls (903 ) bevelled intended to be engaged in a circular groove provided on the hub of the mechanical members.