EP3016848B1 - Pulley - Google Patents

Description

Technical field and state of the art

The present invention relates to the field of pulleys, and more particularly to pulleys allowing the deflection of a rope. US675306 is considered as the closest state of the art, discloses a pulley comprising: a one-piece sheave comprising two opposite longitudinal faces, a transverse central recess, and a concave outer surface forming an annular groove provided to deflect a rope, the recess central and the concave outer surface being fixed relative to each other, a reaa fixing rod, passing through the central recess of the sheave, the fixing rod being in direct contact with the central recess. There are several types of pulley on the market.

A first type of pulley is the sheave for diverting a rope when it passes through the central recess of the sheave (a sheave wheel).

These sheaves with low friction offer a solidity / weight / price to any test, because there is no rotating part. The resistance to friction is obtained only by the fiber of the rope to be deflected and that which serves to fix the sheave. This product is more and more present on the offshore racing boats because it is a guarantee of reliability. Its major disadvantage is that it increases enormously the friction of the rope which passes in its center, and therefore it takes much more energy to maneuver the rope than on a classic pulley.

A second type of pulley comprises a ball sheave, that is to say a pulley with a sheave by means of a ball bearing. This ball bearing offers a very low coefficient of friction. This type of pulley is very efficient and allows the realization of complex effort reduction systems. The disadvantage of these pulleys is that they are expensive when they are intended for heavy loads. They also require maintenance and regular checking due to the presence of the ball bearing. Another disadvantage is that if the axis, the side faces or the point of attachment are broken, then the connection is broken between the rope and the point of attachment and collateral damage results for the system as a whole . In addition, the performance of ball bearings designed for heavy loads is also heavy. For example in the nautical field, this disadvantage is detrimental to the performance of a boat.

The object of the present invention is to overcome these disadvantages and to provide an improved pulley reducing the friction of the rope to be deflected while having a high load resistance, for a reduced weight.

Description of the invention

• un réa monobloc comprenant deux faces longitudinales opposées, un évidement central transversal, et une surface extérieure concave formant une gorge annulaire prévue pour dévier un cordage, l'évidement central et la surface extérieure concave étant fixes l'un par rapport à l'autre,
• un cordage de fixation du réa, traversant l'évidement central du réa, le cordage de fixation étant en contact direct avec l'évidement central,
• un élément écarteur agencé pour écarter le cordage de fixation des faces longitudinales du réa.

The invention proposes a pulley comprising:

• a one-piece sheave comprising two opposite longitudinal faces, a transverse central recess, and a concave outer surface forming an annular groove provided for deflecting a rope, the central recess and the concave outer surface being fixed relative to one another,
• a rope for fixing the sheave, passing through the central recess of the sheave, the fastening rope being in direct contact with the central recess,
• a spacer element arranged to separate the fastening rope from the longitudinal faces of the sheave.

The pulley is used to deflect a rope (long, flexible, resistant, round, consisting of twists) passing through the annular groove of the sheave. The sheave is a wheel-shaped piece used for transmitting motion. The sheave is held in position by the shim of the sheave. The sheave rotates freely around the fixing rope and the spacer element is intended to spread the rope to reduce the friction of the rope of fixation with the sheave.

Compared with the pulley having a ball bearing of the state of the art, this pulley does not require maintenance related to the ball bearing. This advantage due to the lightness, the price and its performance due to its low friction makes the pulley of the present invention very advantageous.

Indeed, the pulley combines resistance lightness, low price and especially low friction. This results for the user a significant gain of maneuverability compared to the use of a sheave when the rope is deflected by the central recess while having the lightness and safety in use under heavy loads.

The spacer element has the function of reducing friction on the sheave. This configuration allows the spacer element to rotate the sheave without being blocked by compression of the fastening rope. Letting the sheave around the fastening rope minimizes friction.

The pulley according to the invention improves its safety of use. For example, in case of rupture of the sheave, the deflected rope remains blocked by the fixing rope. Such a break may be due to an overload on the deviated rope.

According to one aspect of the invention, the spacer element comprises two ends transversely projecting with respect to the longitudinal faces of the sheave, the two projecting ends being arranged to receive the fixing rope in support.

Thus, the fastening rope is spaced laterally from the longitudinal faces of the sheave. In this way, the fastening rope also serves to maintain the sheave in position relative to the spacer element, which facilitates assembly since there is little room and optimizes assembly costs.

According to another aspect of the invention, the spacer element comprises two fastening means arranged on either side of the longitudinal faces of the sheave, the fastening means being provided for fixing the fastening rope to the spacer element.

According to another aspect of the invention, in a transverse plane passing through the axis of rotation of the sheave, the length of the spacer element, measured along a longitudinal axis of the spacer element parallel to the axis of rotation, is greater than a distance separating the longitudinal faces of the sheave, the distance being defined along the axis of rotation of the sheave. In a particular embodiment, the length of the spacer element is at least 1.5 times, and advantageously twice, the distance separating the longitudinal faces of the sheave.

The transverse plane of the pulley is defined when the sheave and the spacer element are assembled. The length of the spacer element is the distance between the two ends of the spacer element measured along a longitudinal axis in the transverse plane passing through the axis of rotation.

Also according to the invention, the fastening cord departs from the sheave in two directions, one on each side of the sheave, the two directions forming between them an angle of between 10 ° to 180 °, and preferably between 80 ° to 120 °. In this way, friction is reduced. The angle is defined in the working position of the pulley, that is to say when the sheave is maintained by the fixing rope.

According to another preference, the spacer element comprises an orientation groove of the sheave, the orientation groove being designed to cap at least part of the sheave.

Thus, the orientation groove makes it possible to maintain the friction sheave in one direction, which prevents the sheave from pivoting or detaching from the spacer element during the load. In addition, this configuration prevents the rope from being able to get out of the sheave.

The fastening cord may comprise at least two strands passing through the central recess of the sheave. Advantageously, the spacer element is arranged to separate the two strands parallel to the longitudinal faces of the sheave. Alternatively, the at least two strands may be joined.

Preferably, the shim of the shim forms an endless loop. For example, the endless loop keeps the spacer element relative to the sheave. This loop can be removed from the spacer element to facilitate assembly and disassembly of the pulley. The endless loop helps maintain the sheave, stabilize the sheave when charging. In this configuration, the spacer element is arranged to receive two straps formed by the fastening rope on either side of the central recess and to allow attachment of the pulley through the two straps.

More generally, the use of the fixing rope for securing the pulley makes it possible to further improve the safety of its use. Indeed, in case of breakage of the spacer element, the deviated rope remains blocked by the fixing rope.

According to another aspect of the invention, the pulley comprises a plurality of separate fastening ropes each passing through the central recess. The pulley may comprise as many spacers as fixing rope, each associated with a fastening rope.

• plusieurs réas monoblocs comprenant chacun deux faces longitudinales opposées, un évidement central transversal, et une surface extérieure concave formant une gorge annulaire prévue pour dévier un cordage, l'évidement central et la surface extérieure concave étant fixes l'un par rapport à l'autre,
• un cordage de fixation associé à chacun des réas et traversant l'évidement central du réa correspondant, le cordage de fixation étant en contact direct avec l'évidement central du réa considéré,
• un élément écarteur agencé pour écarter latéralement les différents cordages de fixation des faces longitudinales des réas correspondants.

According to another aspect of the invention, the pulley comprises:

• a plurality of one-piece sheaves each having two opposite longitudinal faces, a transverse central recess, and a concave outer surface forming an annular groove provided for deflecting a rope, the central recess and the concave outer surface being fixed relative to one another ,
• a fastening cord associated with each of the sheaves and passing through the central recess of the corresponding sheave, the fastening rope being in direct contact with the central recess of the sheave considered,
• a spacer element arranged to laterally separate the various fastening ropes of the longitudinal faces of the corresponding sheaves.

In order to improve the evacuation of the heat generated by the friction of the fastening cord on the sheave, the sheave includes a radiator for convective dissipation of the heat generated by a friction of the fastening cord in contact with the central recess. .

In order to limit the friction of the fastening cord on the sheave, the sheave comprises a cavity for receiving a lubricating product and arranged to lubricate the contact between the fastening cord and the central recess.

In order to facilitate the assembly of the pulley, the fastening rope comprises a closed loop passing through the central recess and an extension intended to fix the pulley.

The pulley may comprise a becket formed by a loop of rope passing through the central recess and being in direct contact with the central recess.

• un second cordage de fixation du réa, traversant l'évidement central du réa et étant en contact direct avec l'évidement central,
• un second réa monobloc comprenant deux faces longitudinales opposées, un second évidement central transversal, et une seconde surface extérieure concave formant une gorge annulaire prévue pour dévier un cordage, le second évidement central et la seconde surface extérieure concave étant fixes l'un par rapport à l'autre,
• un second élément écarteur agencé pour écarter le second cordage de fixation des faces longitudinales des deux réas.

In a violin-type assembly, the pulley further comprises:

• a second string for fixing the sheave, passing through the central recess of the sheave and being in direct contact with the central recess,
• a second one-piece sheave comprising two opposite longitudinal faces, a second transverse central recess, and a second concave outer surface forming an annular groove provided to deflect a rope, the second central recess and the second concave outer surface being fixed relative to one another; the other,
• a second spacer element arranged to separate the second fastening rope longitudinal sides of the two sheaves.

Advantageously, the pulley comprises a means of detecting an overstress of a force entered by the fastening rope.

Advantageously, the pulley comprises a means for measuring temperature.

Brief description of the figures

• la figure 1 représente une vue de face de la présente invention selon un premier mode de réalisation,
• la figure 2 représente une vue en perspective de l'invention selon un premier mode de réalisation,
• la figure 3 représente une vue de face de la présente invention selon une variante du premier mode de réalisation,
• les figures 4a et 4b représentent une variante du premier mode de réalisation,
• la figure 5 représente une autre variante du premier mode de réalisation,
• les figures 6 et 7 représentent un mode de réalisation dans lequel l'élément écarteur forme une structure ayant d'autres fonctions,
• la figure 8 représente un mode de réalisation dans lequel plusieurs réas partagent un même élément écarteur,
• la figure 9 représente un mode de réalisation dans lequel l'élément écarteur est rigidifié,
• la figure 10 représente un mode de réalisation dans lequel le cordage de fixation est réalisé par enroulement filamentaire,
• les figures 11 et 12 représentent deux modes de réalisation dans lequel plusieurs boucles de cordage de fixation sont associées à un même réa,
• la figure 13 représente un mode de réalisation dans lequel un même élément écarteur est associé à plusieurs réas,
• les figures 14 et 15 représentent des réas possédant des moyens d'évacuation de chaleur,
• la figure 16 représente un réa permettant la lubrification du contact avec le cordage de fixation,
• les figures 17 à 20 représentent différents montages d'une poulie conforme à l'invention,
• la figure 21 représente une poulie dans laquelle le cordage de fixation est composite,
• la figure 22 représente une poulie dans laquelle le cordage de fixation est formé à l'aide d'une sangle,
• la figure 23 représente une vue schématique de test de la présente invention.

Other features and advantages of the invention will become apparent in the light of the following description, made on the basis of the accompanying drawings. These examples are given in a non-limiting manner. The description is to be read in conjunction with the appended drawings in which:

• the figure 1 represents a front view of the present invention according to a first embodiment,
• the figure 2 represents a perspective view of the invention according to a first embodiment,
• the figure 3 represents a front view of the present invention according to a variant of the first embodiment,
• the Figures 4a and 4b represent a variant of the first embodiment,
• the figure 5 represents another variant of the first embodiment,
• the figures 6 and 7 represent an embodiment in which the spacer element forms a structure having other functions,
• the figure 8 represents an embodiment in which several sheaves share a same spacer element,
• the figure 9 represents an embodiment in which the spacer element is stiffened,
• the figure 10 represents an embodiment in which the fastening cord is made by filament winding,
• the Figures 11 and 12 represent two embodiments in which several loops of fastening rope are associated with the same sheave,
• the figure 13 represents an embodiment in which the same spacer element is associated with several sheaves,
• the figures 14 and 15 represent sheaves with means of heat evacuation,
• the figure 16 represents a sheave for lubricating the contact with the fastening rope,
• the Figures 17 to 20 represent different assemblies of a pulley according to the invention,
• the figure 21 represents a pulley in which the fastening rope is composite,
• the figure 22 represents a pulley in which the fastening rope is formed using a strap,
• the figure 23 represents a schematic view of the test of the present invention.

Description of Embodiments of the Invention

The Figures 1 and 2 show a first embodiment of a pulley 10 according to the invention. The pulley 10 comprises a sheave 11 comprising two opposite longitudinal faces 12 and 13, a transverse central recess 14, and a concave outer surface 15 forming an annular groove designed to deflect a rope 16. The central recess 14 passes through the sheave 11. one longitudinal face to the other. The sheave 11 is monobloc. In other words, the two longitudinal faces 12 and 13, the central recess 14 and the concave outer surface 15 are fixed to each other. The sheave 11 may be made in a single mechanical part, for example obtained by molding or by machining. Alternatively, the sheave 11 may comprise several mechanical parts made separately and then assembled to form an assembly where the functional surfaces 12, 13, 14 and 15 are all fixed relative to each other.

The sheave 11 can turn on itself about an axis A perpendicular to the two longitudinal faces 12 and 13. The sheave 11 is of revolution about the axis A. The pulley 10 also comprises a fastening cord 17 of the sheave 11 A portion of the fastening cord 17 passes through the central recess 14 of the sheave 11. The fastening cord 17 extends in the central recess 14 substantially along the axis A. The fastening cord 17 may be single-stranded. Alternatively, the fastening rope 17 can be stranded. In the example shown, the fastening cord 17 comprises two strands 18 and 19 which extend on either side of the two longitudinal faces 12 and 13 of the sheave 11.

The pulley 10 comprises a spacer element 20 which is arranged to spread laterally the fastening rope 17 of the longitudinal faces 12 and 13 of the sheave 11. When the sheave 11 rotates, it rubs on the fastening rope 17. The presence of the element spacer 20 reduces this friction.

The spacer element 20 comprises two ends 22 and 23 transversely protruding with respect to the longitudinal faces 12 and 13 of the sheave 11. The two ends 22 and 23 are arranged to receive in abutment the two strands 18 and 19 of the fastening cord 17. In this way, the two strands 18 and 19 maintain the sheave 11 while reducing the friction during the use of the pulley 10. A length L of the spacer element 20 is the distance between the two ends 22 and 23 of the spacer element 20 along a longitudinal axis B parallel to axis A of rotation of sheave 11. To separate fastening rope 17 from longitudinal faces 12 and 13 of sheave 11, length L is greater than a distance M between faces 12 and 13. The distance M is defined along the axis A.

The fact of making the fastening cord 17 in at least two strands makes it possible to limit possible parallelism defects of the two axes A and B. Indeed, the direction of the forces exerted on the sheave 11 by the rope 16 can vary resulting in a rotation of the sheave 11 relative to the spacer 20 about an axis C perpendicular to the two axes A and B. A width I of the spacer element 20 is a distance perpendicular to the length L and separating for each end 22 and 23 the supports of the two strands 18 and 19 on the spacer element 20. The width l limits the rotation of the sheave 11 relative to the spacer element 20 about the axis C. The width l is advantageously greater than the smallest diameter D of the central recess 14. The central recess 14 is of revolution about the axis A. Its diameter, perpendicular to the axis A can be variable, to obtain, for example, a form of diabolo extending around the axis A. The smallest diameter D of the central recess 14 is then present at the axis C. Other forms of the central recess 14 are possible. The central recess 14 can have a cylindrical shape with a constant circular section, an ovoid shape, a hyperboloid shape of revolution ...

In other words, the spacer element 20 is arranged to separate the two strands 18 and 19 parallel to the longitudinal faces 12 and 13 of the sheave 11.

Both strands 18 and 19 may be completely separate. Alternatively, in the embodiment shown on the Figures 1 and 2 , the fastening cord 17 of the shea 11 forms an endless loop, the shea 11 is then maintained by the fastening rope 17 at several places which follow the shape of the spacer element 20. The two strands 18 and 19 of the rope of fixing 17 are defined between the portions of the fastening rope 17 on either side of the sheave 11 between the two longitudinal faces 12 and 13 of the sheave 11 and the spacer element 20. The endless loop is fixed to the spacer element 20 in a groove or recess substantially whose shape matches that of the strands 18 and 19. For example, for strands 18 and 19 with circular section, the grooves for receiving the strands 18 and 19 also have substantially semicircular sections of same diameter as the section of the strands 18 and 19. In this way the fastening rope 17 is held in position relative to the spacer element 20.

In the variant in which the fastening cord 17 of the sheave 11 forms an endless loop, the fastening cord 17 closes on itself by means of two loops 26 and 27 formed by the fastening cord 17 and arranged on both sides. other of the central recess 14.

The spacer element 20 is arranged to receive the two straps 26 and 27 and to allow attachment of the pulley 10 by passing through the two straps 26 and 27. For this purpose, the spacer element 20 comprises an opening 28 allowing an element external to cross the two lugs 26 and 27. In the example shown, this outer element is a rope 29 for fixing the pulley 10.

The fastening cord 17 deviates from the sheave 11 in two directions 31 and 32, one on each side of the sheave 11. The two directions 31 and 32 form between them an angle α of between 10 ° to 180 ° and preferably between 80 ° to 120 °. This angle α is defined mainly by the shape of the spacer element 20 and may vary slightly depending on the forces applied to the rope 16. In the example shown in figure 1 the angle α is 100 °.

The spacer element 20 may also comprise an orientation groove 34 of the sheave 11. The orientation groove 34 opens along the axis C. The orientation groove 34 is designed to cap at least part of the sheave 11. This feature prevents the sheave 11 out of position or the rope 16 to deviate from out of the groove 15 of the sheave 11.

The figure 3 shows a variant of the first embodiment, it is shown the same elements as in the first embodiment. The difference is that the spacer element 20 houses the sheave 11 so that the fastening cord 17 deviates from sheave 11 along the same axis. In other words, the angle α is 180 °. Then, the fastening rope 2 has the shape of the spacer element 20.

The Figures 4a and 4b represent another variant of the pulley 10 comprising a cover 36 to protect the fastening rope 17. The pulley is shown in perspective on the figure 4a and exploded on the figure 4b . The cover 36 can be formed in two parts 36a and 36b.

The figure 5 represents yet another variant of the pulley 10 in which the fixing of the pulley is adapted to a rigid object 40. We find the sheave 11, the spacer element 20 and the fixing rope 17 formed here of the two strands 18 and 19. In this variant, the spacer element 20 has a groove 41 opening parallel to the two longitudinal faces 12 and 13 of the sheave 11. The groove 41 opens between the two lugs 26 and 27. The spacer element 20 comprises a drilling 42 is perpendicular to the groove 41. The groove 41 is intended to receive the rigid object 40 and the bore 42 is intended to receive an axis 43 passing through both the spacer element 20 and the rigid object 40. The axis 43 may be a screw making it possible to link the spacer element 20 to the rigid object 40. The dimensions of the groove 41 and those of the rigid element 40 may be adapted so as to define a precise position of the spacer element 20 on the rigid object 40.

On the figure 5 , there is clearly the width l of the spacer element 20 for improving the holding position of the sheave 11 relative to the spacer member 20. This position retention is particularly advantageous in this embodiment. It cascades to improve the maintenance in position of the sheave 11 with respect to the rigid object 40 via the spacer element 20.

The figures 6 and 7 show a second embodiment. In the same way as the first embodiment, the pulley 50 comprises a sheave 11 comprising two opposite longitudinal faces 12 and 13, a transverse central recess 14, and a concave outer surface 15 forming an annular groove provided to deflect a rope. The pulley 50 also comprises a fastening rope 17 of the sheave 11. A portion of the fastening rope 17 passes through the central recess 14 of the sheave 11. The fastening rope 17 may comprise two strands which extend on either side two longitudinal faces 12 and 13 of the sheave 11.

The pulley 50 also comprises a spacer element 51 comprising two fastening means 52 and 53 arranged on either side of the longitudinal faces of the sheave 11. The fastening means are provided for fixing the fastening cord 17 of the sheave 11 to the spacer element 51. In this way, the fastening cord 17 allows laterally remove the fastening cord 17 of the longitudinal faces 12 and 13 of the sheave 11 and thus increase the angle α. The greater the angle α, the more the friction is reduced.

The spacer element 51 can be made in a structure that can fulfill other functions. In the example shown on the figures 6 and 7 the spacer element 51 is made in a boat mast. Such a mat can be formed in a hollow metal section. A first opening 54 is made in the profile to place the sheave 11. Two other openings 55 and 56 are made in the profile symmetrically with respect to the opening 54. The two openings 55 and 56 allow each end to be fixed. 17. More precisely, the ends of the fastening cord 17 each pass through one of the openings 55 and 56 and a retaining element, respectively 57 and 58, attached to each end makes it possible to retain each end of the fastening cord 17. The attachment means 52 and 53 comprise the openings 55 and 56 and the retaining elements 57 and 58. A boat mast generally has a convex profile. The fastening rope 17 can then be mainly disposed inside the profile. The ends of the fastening cord 17 provided with the retaining elements 57 and 58 emerge outside the mat. The pulley 50 can be used to guide a rope 16 passing through the wall of the mat, for example for a halyard, to hoist a sail. The halyard runs inside the mast and at the foot of the mast, the halyard comes out of the mast to be able to be maneuvered. The pulley 50 allows the halyard to get out of the mast and deflect it for its maneuver. The fastening cord 17 may be an endless loop, the ends of the fastening cord 17 issuing through the openings 55 and 56 may be lugs 59 and 60 formed in the fastening cord 17. The retaining elements 57 and 58 may be fingers alternately slid in the straps 59 and 60. Alternatively, it is possible to have a hook on which each end of the fastening rope 17 is integrally attached or any other means that allows the strands or the ends of the rope to be firmly attached. attachment 17 to the spacer member 51 so as to maintain the sheave 11 in position. The pulley 50 has been described by means of a mat from which it is desired to leave a rope 16 such as a halyard. It is of course possible to implement this variant for any type of wall traversed by a rope 16, the wall being provided with a pulley on which rests the rope 16 to pass through the wall.

The figure 8 represents a third embodiment of a pulley 65 comprising three sheaves 11 arranged parallel to each other in a same axis of rotation sheaves 11. Each shea 11 is identical to the description of the first embodiment or second mode of production.

The pulley 65 also comprises a spacer element 66 comprising three grooves 67 in each of which one of the sheaves 11 can slide. The spacer element 66 is common to the different sheaves 11.

A fastening rope 17 passes through the central recess 14 of each sheave 11 through each of the grooves 67. As before, the fastening rope 17 extends on either side of the two longitudinal faces 12 and 13 of In the configuration shown, the fastening cord 17 forms an endless loop. The spacer element 66 comprises an opening 68 for fixing the pulley 65.

This third embodiment can of course apply regardless of the number of sheaves 11.

The figure 9 schematically represents another embodiment in which the spacer element 71 of a pulley 70 is formed by a element comprising two ends 72 and 73 transversely protruding from the longitudinal faces 12 and 13 of the sheave 11. The two ends 72 and 73 are arranged to fix the ends of the fastening rope 17. In order to withstand the forces generated by the fastening rope 17 on the spacer element 71, it may be metallic.

The figure 10 schematically represents an embodiment in which a fastening cord 75 comprises several loops smaller to have the same load support with a fastening rope 17 of larger diameter. It is possible to make a fastening cord 75 by filament winding. The number of loops made is a function of the effort that the pulley must bear.

According to two other embodiments, represented on the Figures 11 and 12 , it is possible to have several endless loops of fastening rope 17 to allow to withstand greater loads than with a single fastening rope 17. The fastening rope 17 may also be composed of several strands attached to each other . On the figure 11 at each fastening rope loop 17 is associated a spacer member 20. On the figure 12 a spacer element 20 is common to a plurality of fastening rope loops 17.

Both embodiments of the Figures 11 and 12 may make it possible to provide a means of detecting an overstress of a force received by the fastening rope 17. For example, it may be provided that one of the fastening ropes 17 associated with the same sheave 11 has a lower mechanical strength than This lower resistance can be obtained by a smaller section of the fastening rope or by a material whose mechanical strength is weaker. A maximum nominal force that the pulley can take up can be defined by the breaking strength of the weakest fastening rope 17. If this effort is exceeded, the lower strength of the fastening rope 17 breaks and the other (or the other) fastening rope 17 take the relay to ensure continuity of service of the pulley. The breaking of one of the fastening ropes 17 makes it possible to visually detect the exceeding of the nominal force and to warn that a change of pulley is necessary.

Alternatively, other means for detecting an overstress of a force can be implemented in a pulley according to the invention, as for example, with the introduction of one or more strain gauges 77 on the rope of fixing 17, gauges formed for example by a resistive element whose resistance evolves with its elongation. Since the fastening cord 17 is fixed with respect to the fixing of the pulley, it is easy to electrically connect the strain gauge 77 to measurement means external to the pulley along the fastening rope 17 and by fixing the pulley. in order to measure their resistance and consequently to determine the force exerted by the fastening rope 17.

The figure 13 represents an embodiment in which the same spacer element 80 is associated with several sheaves 11. Each sheave 11 has its own fastening rope 17. The various fastening ropes 17 are all held by the same spacer element 80. As shown, the axes of rotation of each sheave 11 are parallel to each other or even common. It is also possible to arrange the sheaves 11 so that the axes of rotation of the different sheaves are not parallel to each other in order to have pulleys that have a variety of use.

The figures 14 and 15 represent sheaves 11 having heat removal means. Indeed, in operation, when the sheave 11 rotates, the friction between the fastening cord 17 and the sheave 11 generates heat and advantageously, the shea 11 comprises a radiator for convective dissipation of the heat generated by the friction of the fastening rope 17 in contact with the central recess 14. On the figure 14 radiator fins 85 are arranged in the annular groove 15. The fins 85 extend for example perpendicular to the axis A. On the figure 15 , fins 87 are disposed on one or on both longitudinal faces 12 and 13. The spacer element 20, not shown in FIG. figure 15 , advantageously makes it possible to avoid contact between the fastening rope 17 and the fins 87.

The figure 16 is a sheave 11 for lubricating the contact with the fastening rope 17. This lubrication limits the heating at the contact between the fastening rope 17 and the central recess 14. The lubrication can be done simply by placing a lubricant product such as a grease on the fastening rope 17. This requires regular interventions to reload the fastening rope 17 into grease. To space these interventions, it is possible to provide in the pulley, a lubricant reservoir. For this purpose, the shea 11 comprises a cavity 89 intended to receive a lubricating product. The cavity 90 is arranged to lubricate the contact between the fastening cord 17 and the central recess 14. The cavity 89 is for example disposed on the C axis.

More generally, the pulley comprises means for evacuating heat generated by the friction of the fastening cord 17 in contact with the central recess 14. These means can be arranged in the sheave 11, as shown in FIGS. figures 14 and 15 or alternatively in the spacer 20 or in the fastening rope 17, for example by means of a channel flowing in the fastening rope 17, the channel being intended to convey a heat transfer fluid for evacuating heat.

Lubrication and heat exchange to the outside help to limit the heating of the pulley. The pulley may also comprise a temperature measuring means, for example located in the fastening rope 17. As for the force sensor, it is possible to place in the fastening cord 17 a temperature sensor 78, for example using a positive or negative temperature coefficient resistance. It is also possible to place on the fixing string an element likely to change color when a temperature threshold is exceeded. The color change can be definitive to allow a memorization of the exceeding of the threshold to alert that a change of pulley is necessary.

The Figures 17 to 20 represent different assemblies of a pulley according to the invention. Each assembly is described with the aid of an embodiment which is particularly suitable for it. It is understood that the various assemblies described can be implemented for the other embodiments. Simple adaptations of the assemblies are then to be realized.

The figure 17 resumes the embodiment shown on the Figures 4a and 4b . The spacer element 20 is hidden under the two parts 36a and 36b of the hood. The fastening rope 17 forms an endless loop and two turns 26 and 27 emerge from the cover 36 at the axis C. One end 90 of the rope 29 passes through the two straps 26 and 27 to secure the pulley 10. The end 29 forms a closed loop 91. It is possible to close the loop 91 by means of a knot formed at the end 90 of the rope 29. Advantageously the loop 91 is closed by means of a splice made on the rope 29.

The figure 18 represents a mounting variant of the pulley 10 in which the fastening rope 17 comprises a closed loop 95 passing through the central recess 14 and an extension 96 intended to fix the pulley 10. More precisely, the same rope is used as a fastening rope through the sheave 11 and as a means of fixing the pulley 10. This assembly can be made by passing through the sheave 11 by an end 97 of the rope. The end 97 is pressed against the spacer element 20 and then closed, for example by means of a splice 98. Outside the closed loop 95 formed by the splice 98, the rope extends to form the extension 96 for fixing the pulley 10.

The figure 19 represents an alternative mounting of the pulley 10 in which a becket 100 is formed by a loop of rope passing through the central recess 14 and being in direct contact with the central recess 14. In the example shown, the becket 100 is formed by a separate rope loop of the fastening rope 17. Alternatively, the fastening rope 17 may be extended to form the becket 100.

The fixing of the pulley 10 is, in the example shown, similar to that described using the figure 17 . The added ringot 100 allows in particular to achieve a fixed point for a rope 16, not shown on the figure 19 . This fixed point can be used in a hoist using the pulley 10. The becket 100 is distinct from the fixing rope 17. The presence of a becket 100 is shown here in a simplified manner. It is possible to place in the loop created by the becket 100, a spacer element 101 arranged to separate the becket 100 of the longitudinal faces 12 and 13 of the sheave 11.

Alternatively, a becket may be formed by a loop of rope attached to the spacer element 20 and independent of sheave 11.

• un second cordage de fixation 117 du premier réa 11, traversant l'évidement central 14 du réa 11 et étant en contact direct avec l'évidement central 14,
• un second réa monobloc 111, semblable au réa 11 et comprenant deux faces longitudinales opposées 112 et 113, un second évidement central 114 transversal, et une seconde surface extérieure concave 115 formant une gorge annulaire prévue pour dévier un cordage, le second évidement central 114 et la seconde surface extérieure concave 115 étant fixes l'un par rapport à l'autre,
• un second élément écarteur 120 agencé pour écarter le second cordage de fixation 117 des faces longitudinales 12, 13, 112 et 113 des deux réas 11 et 111.

The figure 20 represents a mounting variant of the pulley 10 well adapted to achieve a hoist. A common assembly called "violin pulley" consists of a set of two sheaves mounted on a same carrier structure. This arrangement is here adapted to the invention. The fiddle block according to the invention bears the reference 110. Specifically, the pulley 110 comprises, as before, a first sheave 11, a first spacer element 20 and a first fastening rope 17 whose characteristics have been described above. In addition, the pulley 110 comprises:

• a second fastening cord 117 of the first sheave 11, passing through the central recess 14 of the sheave 11 and being in direct contact with the central recess 14,
• a second monobloc sheave 111, similar to shea 11 and comprising two opposite longitudinal faces 112 and 113, a second transverse central recess 114, and a second concave outer surface 115 forming an annular groove provided to deflect a rope, the second central recess 114 and the second concave outer surface 115 being fixed with respect to each other,
• a second spacer element 120 arranged to separate the second fastening cord 117 from the longitudinal faces 12, 13, 112 and 113 of the two sheaves 11 and 111.

According to all embodiments, shea 11 advantageously has the appearance as smooth as possible and should not be deformed under stress. As a result, the possible materials are limited, mainly metals or composites.

• aluminium, pur ou anodisé et ses dérivés ; l'inox, nature ou poli ; le titane traité ou non ; la fonte d'aluminium...
• composites isotropes à base d'injection plastique, chargés de fibre ou non (polyamide, polyéthylène, polyester, polyuréthane, etc...) ; composites anisotropes à base de résines (époxydique, polyester, vinylester, naturel) et de fibres (carbone, verre, kevlar, lin, cellulose)...

For example, here is a non-exhaustive list of metals and possible composites:

• aluminum, pure or anodized and its derivatives; stainless steel, plain or polished; treated or untreated titanium; cast aluminum ...
• isotropic composites based on plastic injection, filled with fiber or not (polyamide, polyethylene, polyester, polyurethane, etc ...); anisotropic composites based on resins (epoxy, polyester, vinylester, natural) and fibers (carbon, glass, kevlar, linen, cellulose) ...

These two examples are not exhaustive and include all metals or composites which are advantageously both lightweight, resistant to corrosion and ultraviolet, while having a high resistance to stress. It can be used metal alloys, metals loaded as well as composite materials type carbon or fiberglass.

Also, according to all the embodiments, the spacer element 20 does not undergo a high compression, so the materials that will be used to build it may be the same as for the sheave 11, with in addition the materials made from molding or plastic injection. It is even possible to manufacture the wooden spacer element 20.

According to all the embodiments, the fastening cord 17 is advantageously a textile which ensures the connection between the sheave 11 and the spacer element 20. First the material must have a high tensile strength and be suitable for the load working pulley. Then, its mechanical characteristics to the friction must be excellent. Few fibers fulfill these two conditions, however it is possible to mix the fibers together. That's why there are a lot of usable materials available.

For example, the fastening cord 17 is made of a single material, such as high modulus polyethylene (or commonly called "dyneema®" or "spectra®", hereinafter referred to as "dyneema"), made of high-performance polyethylene, or a sub-compound. whole polyethylene. This material combines lightness, tensile strength, low elongation, resistance to external aggressions (chemical, organic, ultraviolet), low coefficient of friction, and a reasonable cost. Advantageously, the fact of using a single material is the best ratio efficiency, quality and price.

• âme dyneema, gaine dyneema ou mixte dyneema téflon,
• âme aramide, gaine dyneema ou mixte dyneema téflon,
• âme vectran, gaine dyneema ou mixte dyneema téflon,
• âme PBO (Poly-p-phénylène benzobisoxazole) gaine dyneema ou mixte dyneema téflon,
• âme polyester préétirée, gaine dyneema ou mixte dyneema téflon,
• âme formée par une tresse métallique et gaine dyneema.

In another example, for example represented on the figure 21 it is used a mixture of several materials including for example an inner structural part is called core 125 and a protective part is called sheath 126. The core 125 can be a very tensile fiber and for the sheath 126, it can be use a fiber with a low coefficient of friction. Here are several possible examples:

• dyneema core, dyneema sheath or mixed dyneema Teflon,
• aramid core, dyneema sheath or mixed dyneema Teflon,
• Vectran core, dyneema sheath or mixed dyneema Teflon,
• PBO core (Poly-p-phenylene benzobisoxazole) dyneema sheath or mixed dyneema teflon,
• pre-stretched polyester core, dyneema sheath or mixed dyneema teflon,
• soul formed by a metallic braid and dyneema sheath.

However, the mixture of several fibers is not favored since performance and withstand time are reduced.

The core 125 may also have a treatment such as polyurethane or a subset of polyurethane.

The sheath 126 may be formed of a self-lubricating material to limit friction between the sheave 11 and the fastening rope 17.

The figure 22 represents a pulley variant in which the fastening rope 17 is formed using a strap which can be made using flat woven fibers. The fibers used comprise, for example, high modulus polyethylene, as described above, or any other material capable of withstanding rubbing against sheave 11.

In all other figures, the section of the fastening rope 17 is circular. Any other section of the fastening rope 17 is of course possible without departing from the scope of the invention.

To show the surprising result of the load resistance of the present invention, the pulley of the present invention is compared with two solutions. The first solution is a sheave alone and the second solution is a ball sheave, that is to say it has a ball bearing. The used wheel weighs 12.8 grams for a workload of 1600 kilos and a break at 3500 kilos. The ball mill weighs 118 grams for a work load of 500 kilos and a break at 1500 kilos.

To carry out the tests, it is used two load cells: the first load cell 135 has a capacity of 10 tons and the second load cell 136 has a capacity of 5T. The two load cells were connected in series to measure the error load. The margin of error is 0.5% between the two weighers.

The test relates to the ability of the deflection element to be tested 138 (the pulley of the present invention, the sheave and the ball sheave) and to transmit the load of a tractive force exerted by a hydraulic cylinder 134 connected by a rope to a fixed point 137. For the pulley according to the present invention, the fastening rope 17 is composed of a high modulus polyethylene core and a 6 mm diameter polyester sheath. The angle formed by the rope passing through the deflector element 138 is 180 °.

The first load cell 135 is installed on the load line of the hydraulic cylinder 134, the second load cell 136 is installed on the hung rope at the fixed point 137. The elements are linked together by chair knots. The configuration of the test is visible at the figure 23 .

The first test consisted in testing a single sheave of 35 mm diameter. A dyneema rope passes through the central recess and holds the shea solidly. The load line of the test also passes through the central recess of the sheave. When powering on, it was noticed that the rope slips off by emitting a characteristic sound of a high friction force. Table of results with one of the measurements obtained by the scales: Measuring the load between the cylinder and the sheave Measuring the load between the sheave and the fixed point Loss in kg in kg in kg in% 204 114 90 44.11764706 272 154 118 43.38235294 354 195 159 44.91525424 435 229 206 47.35632184 493 262 231 46.85598377 546 274 272 49.81684982 That is an average of loss in% of the load 46.07

It is observed a 45% loss of load after the sheave, so most of the force is absorbed by the friction induced. During the inspection of the rope, we notice a wear of the rope at the point of contact with the sheave, characterized by a partial rupture of the fibers as well as a partial fusion of the fibers between them due to the heating generated by the friction forces . The sheave was not damaged.

The second test concerns the ball bearing diameter 57 mm. This test was performed under the same conditions as for the only one. In this test, the load line passes through the groove of the ball sheave.

Here is the table of results for the ball rack: Measurement of the load between the cylinder and the ball sheave Measuring the load between the ball sheave and the fixed point Loss in kg in kg in kg in% 93 85 8 8.602150538 118 111 7 5.93220339 213 189 24 11.26760563 291 257 34 11.6838488 340 305 35 10.29411765 415 358 57 13.73493976 446 400 46 10.31390135 557 four hundred ninety seven 60 10.77199282 That is an average of loss in% of the load 10.33

After dismantling the system, no further damage to the rope was noticed. However, the metal element for fixing the ball sheave is deformed. Indeed, with about 500 kilos on the rope and an angle of 180 °, the load on the ball sheave is close to a ton, while its theoretical workload is 500 kilos, so the pulley is damaged.

The third test relates to the pulley of the present invention with an angle α of 100 °. This test was performed in the same conditions as for the ball sheave, but the maximum tensile load was pushed because the workload is greater for the pulley of the present invention. The line of charge passes through the groove of sheave 1. Measuring the load between the cylinder and the pulley Measuring the load between the pulley and the fixed point Loss in kg in kg in kg in% 291 282 9 3.092783505 235 214 21 8.936170213 403 365 38 9.429280397 349 316 33 9.455587393 445 403 42 9.438202247 468 433 35 7.478632479 529 469 60 11.34215501 544 499 45 8.272058824 582 531 51 8.762886598 629 575 54 8.585055644 That is an average of loss in% of the load 8.48

After dismantling the system, no damage is observed on the sheave 11 of the pulley according to the invention. The integrity of the pulley is retained. In addition, even under load the sheave 11 can rotate.

During the first test with the sheave alone, it was found a high pressure loss thus a very limited efficiency and irreversible damage to the rope with the rupture of the soul and their partial melting. This damage is not found in the second test and the third test.

The second test shows the limits of the ball sheave with a load of 500kilos on the rope. Its efficiency is much better than the first test because the pressure loss is only about 10%. The ball sheave transmits well efforts and respects the entirety of the rope during its use. The disadvantage of the ball bearing remains its price, 3 to 4 times greater than a pulley according to the present invention, and its weight is 7 to 8 times greater compared to a pulley according to the present invention.

The pulley of the present invention shows truly effective results in all points of view. It is thus found that the transmission of the force is better than on the ball sheave, which proves the real effectiveness of the present invention.

Claims (20)

1. Pulley comprising:

   • a monobloc sheave (11) comprising two opposing longitudinal faces (12, 13), a transverse central recess (14) and a concave outer surface which forms an annular groove (15) which is provided to redirect a rope (16), the central recess (14) and the concave outer surface (15) being fixed relative to each other,

   • a fixing rope (17) of the sheave (11), extending through the central recess (14) of the sheave (11), the fixing rope (17) being in direct contact with the central recess (14),

   • a spacer element (20) which is arranged to space the fixing rope (17) apart from the longitudinal faces of the sheave (11).
2. Pulley according to claim 1, characterised in that the spacer element (20) comprises two ends (22, 23) which protrude transversely relative to the longitudinal faces (12, 13) of the sheave (11), the two protruding ends (22, 23) being arranged so as to receive the fixing rope (17) in abutment.
3. Pulley according to either of the preceding claims, characterised in that the spacer element (51) comprises two fixing means (52, 53) which are arranged at one side and the other of the longitudinal faces (12, 13) of the sheave (11), the fixing means (52, 53) being provided to fix the fixing rope (17) to the spacer element (51).
4. Pulley according to any one of the preceding claims, characterised in that the fixing rope (17) moves away from the sheave (11) in two directions (31, 32), one at each side of the sheave (11), in that the two directions (31, 32) together form an angle (α) between 10° and 180°, and preferably between 80° and 120°.
5. Pulley according to any one of the preceding claims, characterised in that the spacer element (20) comprises an orientation groove (34) of the sheave (11), the orientation groove (34) being provided to cover at least a portion of the sheave (11).
6. Pulley according to any one of the preceding claims, characterised in that the fixing rope (17) comprises two strands (18, 19) which extend through the central recess (14) of the sheave (11).
7. Pulley according to claim 6, characterised in that the spacer element (20) is arranged to space apart the two strands (18, 19) parallel with the longitudinal faces (12, 13).
8. Pulley according to either claim 6 or claim 7, characterised in that the fixing rope (17) forms an endless loop, in that the spacer element (20) is arranged to receive two cringles (26, 27) formed by the fixing rope (17) at one side and the other of the central recess (14) and to enable the pulley (10) to be fixed by extending through the two cringles (26, 27).
9. Pulley according to any one of claims 1 to 5, characterised in that the fixing rope (17) comprises at least two strands (75) which extend through the central recess (14) of the sheave (11) and in that the at least two strands (75) are connected.
10. Pulley according to any one of the preceding claims, characterised in that it comprises a plurality of separate fixing ropes (17) which each extend through the central recess (14).
11. Pulley according to claim 10, characterised in that it comprises as many spacers (20) as fixing ropes (17), each associated with a fixing rope (17).
12. Pulley according to any one of the preceding claims, characterised in that it comprises:

    • a plurality of monobloc sheaves (11) each comprising two opposing longitudinal faces (12, 13), a transverse central recess (14) and a concave outer surface which forms an annular groove (15) which is provided to redirect a rope (16), the central recess (14) and the concave outer surface (15) being fixed relative to each other,

    • a fixing rope (17) which is associated with each of the sheaves (11) and which extends through the central recess (14) of the corresponding sheave (11), the fixing rope (17) being in direct contact with the central recess (14) of the sheave (11) in question,

    • a spacer element (80) which is arranged to laterally space apart the different fixing ropes (17) of the longitudinal faces (12, 13) of the corresponding sheaves (11).
13. Pulley according to any one of the preceding claims, characterised in that the sheave (11) comprises a radiator (85, 87) which enables dissipation by means of convection of the heat generated by a friction of the fixing rope (17) in contact with the central recess (14).
14. Pulley according to any one of the preceding claims, characterised in that the sheave (11) comprises a cavity (90) which is intended to receive a lubrication product and which is arranged so as to lubricate the contact between the fixing rope (17) and the central recess (14).
15. Pulley according to any one of the preceding claims, characterised in that the fixing rope (17) comprises a closed loop (95) which extends through the central recess (14) and an extension (96) which is intended to fix the pulley (10).
16. Pulley according to any one of the preceding claims, characterised in that it comprises a becket (100) formed by a rope loop which extends through the central recess (14) and which is in direct contact with the central recess (14).
17. Pulley according to any one of claims 1 to 15, characterised in that it further comprises:

    • a second fixing rope (117) of the sheave (11), which extends through the central recess (14) of the sheave (11) and which is in direct contact with the central recess (14),

    • a second monobloc sheave (111) which comprises two opposing longitudinal faces (112, 113), a second transverse central recess (114), and a second concave outer surface which forms an annular groove (115) which is provided to redirect a rope (16), the second central recess (114) and the second concave outer surface (115) being fixed relative to each other,

    • a second spacer element (120) which is arranged to space apart the second fixing rope (117) from the longitudinal faces (12, 13, 112, 113) of the two sheaves (11, 111).
18. Pulley according to any one of the preceding claims, characterised in that it comprises a means for detecting that a force (77) taken up by the fixing rope (17) has been exceeded.
19. Pulley according to any one of the preceding claims, characterised in that it comprises a temperature measuring means (78).
20. Pulley according to any one of the preceding claims, characterised in that the spacer element (66) comprises at least one groove (67) in which the sheave (11) is slid.

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