ES2970567T3 - One-way travel pulley - Google Patents

Abstract

The pulley (1) comprises two pulleys (2) arranged in line with grooves that define a circulation axis of a cable (3). A blocker (12) allows the movement of the pulley (1) along the cable (3) in a first direction and prevents the movement of the pulley (1) in a second opposite direction. The blocker (12) defines a slot (13) with two opposite side walls (12a, 12b) connected by an end wall. The lock (12) can rotate between the first and second positions. The cable circulation axis (3) separates the two side walls (12a, 12b). The first side wall (12a) is capable of moving along the axis of circulation of the cable (3). The rotation of the blocker (12) between the first position and the second position occurs around an axis of rotation that passes through the axis of circulation of the cable (3) to move the two side walls (12a, 12b) along the axis. cable circulation (3). (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

One-way travel pulley

Technical field

The invention relates to a pulley.

Previous technique

In adventure parks, descending along a zip line is an appreciated activity. The user installs the pulley on a cable so that it slides along the cable from the start area to the finish area. The tension applied to the cable between the departure zone and the arrival zone is configured so that a user of average weight can reach the arrival zone with a small impulse. The tension applied to the cable is low enough so that there is a weak zone just in front of the landing zone.

As a consequence, the cable ascends near the arrival area and the user climbs along the cable thanks to the speed acquired during the descent. However, when the user does not weigh enough, the speed acquired is not enough for them to reach the finish area. As a consequence, the pulley slows down as it approaches the arrival area until it stops moving and then moves in the opposite direction.

To avoid this problem and facilitate the user's recovery, it is especially advantageous to provide a pulley that is provided with a non-return system. The anti-return system is configured to enable the circulation of the pulley on the cable in a first direction of circulation and to prevent circulation in the other direction.

Said pulley is described in document US 2016/0355197 which provides for the use of a rotating cam. In circulation along the cable, the axis of rotation of the cam is substantially horizontal and perpendicular to the longitudinal axis of the cable.

During antegrade circulation of the pulley, friction between the cable and the cam causes the cam to lift to slide along the cable. When the pulley is subjected to a force that causes it to move rearward, the cam is not urged to rise relative to the cable. On the contrary, the contact surface between the cam and the cable increases, which increases the friction between the cam and the cable. The cam is designed as a self-locking mechanism so that it blocks the pulley and thus prevents backward movement. The cam raises the rear sheave of the pulley. Apparently, this construction is not as simple to implement as it seems so the effectiveness of the cam depends strongly on the diameter of the associated cable. As there are numerous cable diameter standards between 12 and 13 mm, the operation of the pulley varies in a non-negligible way from one installation to another.

The BORNACK company that markets a pulley that has a roller configured to rotate in only one direction has proposed another configuration. This solution is of no interest since it is expensive and depends heavily on the friction that exists between the cable and the roller, that is, it is very difficult or even impossible to maintain an effective lock by means of a roller that slides along the cable. .

Object of the invention

An object of the invention is to provide a pulley provided with an anti-return system that is easy to implement and economical while ensuring effective blocking of the pulley in a retrograde direction. For this purpose, the pulley includes:

-a pair of sheaves arranged in a line, such that the pair of sheaves has grooves that define an axis of circulation of the cable in the pulley and that corresponds to the longitudinal axis of the cable,

-a blocker that can move between a first position that makes possible the movement of the pulley along the longitudinal axis of the cable in a first direction and a second position that prevents the movement of the pulley in a second opposite direction, such that the blocker defines a slot intended to cooperate with the cable, the slot including opposite first and second side walls joined by a bottom wall, the blocker being arranged so that the axis of circulation of the cable passes between the two side walls.

The pulley is notable because at least the first side wall can move according to the axis of circulation of the cable and because the movement of the blocker between the first position and the second position corresponds to a movement of the first side wall according to the second direction to move the first and second side walls along the cable circulation axis and lock the pulley on the cable by eccentric mechanism.

In one development, the blocker is freely mounted in a direction perpendicular to the axis of circulation of the cable and perpendicular to the axes of rotation of the sheaves, so that the weight of the blocker drags one of the side walls of the slot or the bottom wall towards the cable circulation axis.

Advantageously, the blocker is arranged so that the weight of the blocker brings the bottom wall and the axis of circulation of the cable closer together.

Preferably, the first and second side walls are mounted so that they can move according to the axis of circulation of the cable, when the blocker moves from the first position to the second position, the displacement distance of the first side wall is greater than the displacement distance of the second distance according to the cable circulation axis.

In a particular embodiment, the pulley is configured to cooperate with a cable of a first diameter and in which the separation distance between the first and second side walls is greater than the first diameter at least by a height greater than half of the first diameter. so that the first and second side walls are separated by one cable diameter in the first position and in the second position.

Advantageously, the pulley includes a box that houses the blocker, so that the box defines stops that limit the movement of the first side wall and the second side wall according to the axis of circulation of the cable in the first direction.

In a preferred configuration, the box and the blocker define a functional clearance according to a direction that passes through the two side walls of the slot and the axis of circulation of the cable.

Preferably, the box and the blocker define a functional clearance according to a direction that passes through the bottom wall and the axis of circulation of the cable.

In another development, the jammer is removably mounted with respect to the housing.

Preferably, the box prevents rotation of the blocker about an axis of rotation parallel to the axes of rotation of the rollers.

In a particular embodiment, the box is mounted so that it cannot move with respect to a support bracket on which the rollers rest when the blocker moves between the first and second positions. In an advantageous configuration, the box is removably mounted with respect to a support bracket on which the sheaves rest.

Preferably, the box defines first and third stops that limit the displacement of the first side wall of the blocker according to the axis of circulation of the cable and second and fourth stops that limit the displacement of the second side wall of the blocker according to the axis of circulation of the cable. , the distance between the second and fourth stops being less than the distance between the first and second stops according to the axis of circulation of the cable.

In another development, the box defines first and second stops configured to form a support plane of the blocker in the first position perpendicular to the axis of circulation.

Brief description of the drawings

Other advantages and characteristics will emerge more clearly from the following description of particular embodiments and implementations of the invention given by way of non-limiting examples and represented in the accompanying drawings, in which:

Figure 1 illustrates, schematically, in perspective, a first embodiment of a pulley with an anti-return device;

Figure 2 illustrates, schematically, in perspective, a second embodiment of a pulley with an anti-return device;

Figure 3 illustrates, schematically, a pulley with an exploded view of the anti-return device;

Figure 4 illustrates, schematically, in cross-sectional view according to plane A-A at the height of the anti-return device;

Figure 5 illustrates, schematically, in side view a pulley provided with an anti-return device; Figure 6 represents, schematically, in top view and in cross section in the anti-return device according to the plane B-B, a pulley whose anti-return device is in a circulation position; Figure 7 represents, schematically, in top view and in cross section in the anti-return device according to the plane B-B, a pulley whose anti-return device is in a locking position, Figure 8 represents, schematically, in front view , a pulley whose anti-return device is in a position that makes movement possible, the cable being substantially rectilinear,

Figure 9 illustrates, schematically, in side view and in cross section in the anti-return device according to a C-C plane, a pulley provided with an anti-return device in a position that makes movement possible, the cable being substantially rectilinear;

Figure 10 represents, schematically, in front view, a pulley whose anti-return device is in a position that makes movement possible with the cable folded by the pulley,

Figure 11 illustrates, schematically, in side view and in cross section in the anti-return device according to a plane C-C, a pulley provided with an anti-return device in a position that makes movement possible, the cable being substantially folded by the pulley,

Figure 12 illustrates, schematically, in perspective, a first embodiment of a pulley with an anti-return device,

Figure 13 illustrates, schematically, in side view a pulley provided with an anti-return device according to Figure 12,

Figures 14 and 15 illustrate, schematically, in top view and in cross section in the anti-return device according to the C-C plane, a pulley whose anti-return device is in a circulation position or in a blocking position.

Description of embodiments

As illustrated in Figures 1 to 7, a pulley device 1 includes a pair of sheaves 2 or rollers that are advantageously of identical structures. Pair of sheaves 2 is mounted in line. The two sheaves 2 have a groove so that the in-line assembly of the two grooves defines an axis of circulation of a cable 3 in the pulley. The circulation axis of cable 3 corresponds to, or is parallel to, the longitudinal axis of cable 3.

Each sheave 2 is mounted in rotation on an axis 4, preferably in free rotation. The two axles 4 are fixed on a support bracket 5. The support bracket 5 advantageously has an inverted U shape. The support bracket 5 may be a metal support bracket. The support stirrup 5 can be formed by a deformed sheet to define a U or substantially a U. The support stirrup 5 can be made by an assembly of several elements and for example by first and second flanges. The support stirrup 5 defines first and second fins 6 and 7.

Said device is advantageously used for transporting a person through the air during a zip line ride on a rope or safety cable (not shown). Pulley 1 circulates along cable 3 which is fixed. The two rollers 2 are mounted so that they can move in rotation by means of two rotation axes 4. The two rotation axes 4 are installed parallel to each other. The two axes of rotation 4 define two different axes of rotation. The two axes of rotation advantageously belong to the same plane that divides each roller into two equal parts.

In a particular embodiment, the stirrup 5 has two opposing fins 6 and 7. The two axles 4 are advantageously mounted fixed on the two fins 6 and 7.

Pulley 1 can be prepared in different ways. In the configuration illustrated in Figure 1, the first fin 6 extends under the sheaves 2. The first fin 6 is associated with a mobile finger 8 that cooperates with the second fin 7 to close a housing for the cable 3 in the pulley 1. The moving finger 8 has an actuation button 9 which is used to unlock the moving finger 8 and move it towards an open position. In the open position, the mobile finger 8 is separated from the second fin 7 to be able to insert or extract the cable 3.

In the configuration illustrated in Figure 2, the support bracket 6 defines two through holes that make it possible to pass a carabiner 10. The carabiner 10 is installed between the two sheaves 2. The opening of the mobile finger of the carabiner 10 allows insertion and remove cable 3. Carabiner 10 passes through the support bracket 5 which defines the mechanical connection between carabiner 10 and cable 3. Carabiner 10 is mounted in the through hole to define the mechanical connection between the user and the cable 3. When the user is suspended by means of the carabiner 10, the carabiner 10 rests on the support stirrup 5 which is retained by the cable 3.

In all illustrated embodiments, the pulley 1 defines a cable insertion housing 3, although other configurations are possible. The pulley 1 circulates along the longitudinal axis of the cable 3, relying on the two sheaves 2, inside the grooves.

The pulley 1 includes a non-return device 11 that is configured to make it possible to move the pulley 1 with respect to the cable 3 in only one direction. The anti-return device 11 makes it possible to move the pulley 1 with respect to the cable 3 along the longitudinal axis of the cable 3 in a first direction called anterograde direction. The anti-return device 11 prevents the movement of the pulley 1 with respect to the cable 3 in a second direction opposite to the first direction and called the retrograde direction.

The anti-return device 11 is advantageously fixed to the support bracket 5. Advantageously, the anti-return device 11 is fixed removably with respect to the support bracket 5.

As illustrated in Figures 3 to 7, the anti-return device 11 includes a blocker 12 that defines a slot 13. The blocker 12 has first and second side walls 12a and 12b that are joined together by a bottom wall so that it defines the slot 13. The slot 13 cooperates with the cable 3 in order to ensure the locking of the pulley in the retrograde direction without obstructing forward progression. The cable 3 circulates inside the slot 13. The blocker 12 is mounted so that it can move between a first position called the circulation position and a second position called the blocking position. In the circulation position, the blocker 12 makes it possible to move between the cable 3 and the pulley 1 in the first direction. In the blocking position, the blocker 12 rests on the cable 3, which prevents the movement of the pulley 1 in the second direction. In the locking position, the locking device 12 rests on the two opposite walls of the cable. The blocker is placed on an eccentric mechanism in order to lock the cable on the pulley.

Between the first position and the second position, the blocker 12 moves in an angular direction. The movement of the blocker 12 can be a pure rotation, but it can also be a mixture between a rotation and a translation or a more complex movement with a rotation. From the first position to the second position, at least the first side wall 12a of the blocker 12 moves according to the axis of circulation of the cable 3 to follow the movement of the cable 3, that is, according to the second direction. It is possible that the two side walls can be moved, but it is advantageous that the displacement of the second side wall 12b is reduced as much as possible to ensure good compactness of the anti-return device 11.

Between the first position and the second position, the value of the displacement of the first side wall 12a is different from the value of the displacement of the second side wall 12b according to the axis of circulation of the cable 3. In other words, the first and second side walls second 12a and 12b move different distances according to the axis of circulation of the cable 3 due to the rotation of the blocker 12. The rotation of the blocker 12 causes a displacement of the side walls 12a and 12b according to the axis of circulation of the cable 3. Said Otherwise, the two contact areas between the cable 3 and the side walls 12a and 12b belong to two different planes perpendicular to the longitudinal axis of the cable.

Between the first position and the second position, the orientation of the blocker 12 changes. The orientation of the blocker 12 can be represented by the value of the angle that exists between the longitudinal axis of the cable 3 and the axis that joins the two side walls 12a and 12b. Preferably, the value of the angle evolves continuously in absolute value. It is advantageous to provide that the blocker 12 does not have an axis of rotation that joins the blocker with the support bracket or with the rest of the pulley.

As the blocker 12 rotates, the distance accessible to the cable 3 to pass into the slot 13 decreases, and the friction increases until the moment in which the blocker 12 becomes immobilized on the cable 3 and immobilizes the double pulley 1.

When the pulley 1 moves in the first direction, the cable 3 rubs against one or other of the side walls of the blocker 12, which causes the blocker 12 to move towards the first position or to maintain it in the first position, which is a position. that makes movement possible. In the illustrated embodiment, when the pulley 1 moves according to the first direction, the cable pushes the blocker 12 towards a stop in a configuration in which the opening defined by the slot 13 is maximum. When the pulley 1 moves in the second direction, due to friction, the cable 3 applies a force to the blocker 12 to move it towards the second position. The first side wall 12a moves in the second direction. The two side walls move until the second side wall reaches a stop and locks. The first side wall 12a continues to move due to the cable 3 which rotates the blocker 12. The blocker 12 rotates until the second side wall 12b comes into contact with the cable 3 and simultaneously in contact between the cable 3 and the first wall 12a. The opposite sides of the cable 3 rest on the first and second side walls so that the cable 3 is held fixed with respect to the cable. The first side wall rests on the stop which blocks the blocker 12 and blocks the pulley 1 on the cable 3. The blocker 12 can no longer rotate, which blocks the movement of the pulley with respect to the cable 3.

The rotation of the slot 13 is carried out around an axis that passes through the cable 3, that is, which is located between the two side walls of the slot 13. The value of the angle of rotation to obtain the blocking of the cable is defined by the diameter of the cable and the width of the slot. Thus, a blocker 12 is able to ensure the blocking of various cable diameters. However, to increase the reactivity of the blocker 12 and/or to ensure its compactness (i.e., limit the angular range to obtain the finest cable blocking), it is advantageous to use slots adapted to cable ranges 3. To increase versatility of the pulley, it is advantageous to form a first groove with a first width at one end and to form a second groove with a second width at the other end of the blocker. To adapt to the diameter of the cable, simply turn the blocker 12 to move from one slot to another.

Advantageously, in the circulation position, the two side walls of the slot 13 do not come into contact simultaneously with the cable 3, which significantly reduces the friction caused by the pulley in its movement in the first direction. The width of the slot 13 is slightly greater than the diameter of the cable 3. The pulley 1 is intended to cooperate with a cable of diameter D. The diameter is advantageously between 12 mm and 13 mm. Conventionally, adventure parks are equipped with 12 mm, 12.7 mm and/or 13 mm cables. In an advantageous embodiment, the distance separating the two side walls of the slot 13 is greater than the diameter D by a distance at least equal to half the diameter and preferably less than twice the diameter. In this way, the blocker 12 comes into contact with the cable 3 on the two diametrically opposite sides in the blocking position. This configuration makes it possible to have a particularly effective blocker 12 and, in particular, more effective than a slot configuration 13 that is more restricted.

It is particularly advantageous to provide that the slot 13 is configured so that the bottom wall comes into contact with the cable 13 in the first position, in the second position and between these two positions. It is preferable that the blocker 12 is mounted so that it can move perpendicular to the plane containing the axes of rotation of the wheels 2 and that the side walls extend along an axis perpendicular to the plane containing the axes of rotation of the wheels 2.

As illustrated in Figures 4 and 5, it is advantageous that the blocker is mounted in a manner free of movement in a direction perpendicular to the axis of circulation of the cable and perpendicular to an axis that joins the two lateral faces, which allows during the circulation of the pulley in the first direction of circulation has a movable blocker to reduce the friction forces linked to the blocker 12 in the first direction of circulation. As illustrated in Figures 8, 9, 10 and 11, the freedom of movement of the blocker 12 with respect to the cable allows a blocking position to be maintained regardless of the deformation of the cable attached to the pulley. Figures 9 and 11 show the vertical displacement of the jammer imposed by the deformation of the cable. The blocker remains in a position that makes movement possible and the movement of the blocker does not modify the engagement of the blocking position, unlike the previous technique.

As illustrated in Figures 4 and 5, it is also advantageous that the blocker is mounted free of movement in a plane perpendicular to the axis of circulation of the cable according to the direction that joins the lateral faces, which allows during the circulation of the pulley in the first direction of circulation having a movable blocker to reduce the friction forces linked to the blocker 12 in the first direction of circulation.

Advantageously, the anti-return device 11 defines a box 14 containing the blocker 12. The blocker 12 is mounted so that it can move in the box 14. The blocker 12 defines stops that limit the movement of the blocker 12 in the first position and in the second position. The position of the stops defines the value of the angular displacement of the blocker 12 between the first and second positions.

In the illustrated embodiment, the box 14 is configured to define a functional clearance with the blocker 12. The functional clearance makes possible a movement of the blocker 12 perpendicular to the axis of circulation of the cable 3 and advantageously parallel to the axis of rotation of the sheaves. 2. The functional clearance allows the position of the slot 13 to be adapted with respect to the position of the cable 3 and with respect to the box. The functional clearance makes it possible to limit the friction between the blocker 12 and the cable 3 when the pulley 1 moves in the forward direction while ensuring continuous or almost continuous contact between the blocker 12 and the cable 3.

It is also advantageous to provide that there is another functional clearance between the cable 3 and the blocker 12 in a direction parallel to the axis of rotation of the blocker 12 and in a plane perpendicular to the longitudinal axis of the cable 3. The functional clearance makes it possible to make free movement of the blocker above cable 3 during pulley movement. The weight of the blocker 12 supports the blocker 12 on the cable 3, which ensures continuous or almost continuous contact between the blocker 12 and the cable 3. The weight of the blocker 12 ensures sufficient friction with the cable 3 to detect the direction of movement. displacement of the cable 3 and consequently modify the position of the blocker 12. The functional clearance makes possible a translation of the blocker perpendicular to the axis of circulation of the cable 3 and advantageously perpendicular to the plane containing the axes of rotation of the sheaves 2.

During its movement, the position of the cable on the pulley changes according to the movements of the user, the two functional clearances ensure continuous or almost continuous contact between the cable 3 and the blocker 12 without introducing significant friction.

In a particular embodiment, the blocker 12 is mounted so that it can move around an axis of rotation that is perpendicular to the longitudinal axis of the cable 3 and perpendicular to the axis of rotation of the sheaves 2. The axis of rotation of the blocker 12 is perpendicular to the plane containing the axes of rotation of the two axes of rotation when the sheaves 2 are identical. This embodiment is more effective than the configuration in which the slot is rotated 90° in the plane perpendicular to the axis of circulation of the cable 3 since the weight of the blocker 12 does not generate a force that imposes continuous or almost continuous contact thereof. side wall over cable 3.

When the pulley 1 circulates in the anterograde direction, the blocker 12 rubs against the cable 3, which pushes the blocker 12 against the first and second stops 15a, 15b of the side walls of the box 14 so that the blocker 12 is located in the circulation position. When the pulley 1 attempts to circulate in the retrograde direction, the blocker 12 rubs against the cable 3, which pushes the blocker 12 against the third and fourth stops 15c and 15d. One of the side walls of the blocker 12 moves over a short distance or does not move at all or hardly moves at all, while the other side wall moves a much longer distance to realize the angular displacement of the blocker 12.

The box 14 defines the first and third stops 15a and 15c that limit the displacement of the first side wall 12a of the blocker 12 according to the axis of circulation of the cable 3. The stops 15a and 15c are separated by the first side wall 12a. The second and fourth stops 15b and 15d limit the displacement of the second side wall 12b of the blocker 12 according to the axis of circulation of the cable 3. The stops 15b and 15d are separated by the second side wall 12b.

The distance between the second and fourth stops 15b and 15d is less than the distance between the first and second stops 15a and 15c according to the axis of circulation of the cable 3. Advantageously, the distance between the second and fourth stops 15b and 15d defines a small functional clearance so that the blocker 12 can move along the axis of circulation of the cable 3, for example by 1 mm or 2 mm.

In an advantageous configuration, the box 14 is fixedly mounted with respect to the stirrup 5 when the blocker 12 moves between the first position and the second position. This configuration ensures better functioning of the blocker. For example, the box 14 is fixed to the stirrup 5 by means of a screw 15.

Preferably, the box 14 is configured to prevent rotation of the blocker 12 perpendicular to the axis of circulation of the cable 3 and parallel to the axis of rotation of the sheaves 2. In the illustrated configuration, the box 14 is removably mounted with respect to to the support stirrup 5. This makes it possible to form a double pulley that can be provided or not provided with the anti-return system 11.

The blocker 12 is advantageously formed by a metal plate, for example a steel plate defining the slot 13. The blocker may be in the form of a flat plate.

The box 14 is advantageously closed by a cover 16.

In the illustrated embodiments, the blocker 12 is formed by two parallel opposite faces and the box 14 defines a support plane perpendicular to the axis of circulation of the cable 3. During the movement of the pulley according to the first direction of movement, the cable pushes the blocker against the support plane. Other forms of blockers are possible in cooperation with a support plane that is separated from a perpendicular position to obtain the first position and the second position.

The illustrated configuration lacks springs that push or pull the blocker in order to gain compactness. However, it is possible to provide for the use of a spring that is configured to push or pull the blocker 12 in order to place it in the second position in the absence of effort. When an effort is applied to the pulley to move it according to the first direction of movement, cable 3 contracts the spring and modifies the angular opening of the slot. This embodiment is less advantageous than the previous one, since the spring causes the blocker 12 to continually rub against the cable.

Figures 12, 13, 14 and 15 illustrate a particular embodiment of a pulley referred to above. The pulley has a blocker 12 mounted in rotation and preferably mounted only in rotation. In the illustrated embodiment, the axis of rotation is defined by a rotation axis 17 mounted at one end of the blocker 12. The box 14 defines a cavity that cooperates with the axis 17 to define the rotation of the blocker 12 perpendicular to the longitudinal axis of the cable and preferably perpendicular or almost perpendicular to the axis of rotation of the rollers 2.

Figure 14 illustrates the forward movement of the pulley with respect to cable 3. The direction of circulation is represented by the arrow. Figure 15 illustrates the reverse movement of the pulley with respect to cable 3. The desired direction of movement is represented by the arrow.

When the pulley moves forward, the cable pushes the blocker against the box so that the opening provided in the blocker 12 is greater than or equal to the diameter of the cable 3. The pulley can move along the cable with a weak friction induced by the blocker 12. On the contrary, when the pulley tries to move in the other direction, the friction between the cable and the blocker pushes the blocker away from the end side wall of the box. The blocker 12 rotates, reducing the effective width of the slot 13. The more the blocker 12 rotates and the width decreases, the friction increases until the blocker locks the pulley on the cable. As in the previous configurations, the blocker can define two different slot widths 13 to accommodate at least two different diameters of cable 3. It is advantageous if the box defines a cavity having a substantially circular section to receive an axis of rotation having a substantially circular section.

As for the previous embodiments, the box 14 can define the first and second stops 15a, 15b that fix the position of the blocker in the position that makes forward movement of the pulley possible. It is also possible that the box defines a third stop 15c and a fourth stop 15d. However, it is preferable that the cavity defines an arc of a circle that extends more than half the circle to maintain the axis of rotation in the cavity when the cable pulls on the axis of rotation to cause rotation of the blocker 12. The figures 14 and 15 represent a cavity that forms at least % of a circle and that maintains the axis of rotation of the blocker in the cavity.

As indicated above, this embodiment allows having a blocker that rotates around the axis of rotation defined by the cavity and the axis of rotation. This also makes possible the translational movement of the blocker along the longitudinal axis of the cavity and the blocker.

Claims (15)

1. Pulley (1) intended to move along a longitudinal axis of a cable (3) of a first diameter comprising: - a pair of rollers (2) arranged in a line, such that the pair of rollers (2) has grooves that define an axis of circulation of the cable (3) in the pulley (1) and that corresponds to the longitudinal axis of the cable (3 ), - a blocker (12) that can move between a first position that makes possible the movement of the pulley (1) along the longitudinal axis of the cable (3) in a first direction and a second position that prevents the movement of the pulley (1). ) according to a second opposite direction, such that the blocker (12) defines a slot (13) intended to cooperate with the cable (3), the slot (13) including first and second opposite side walls (12a, 12b) joined by a bottom wall, the blocker (12) being arranged so that the axis of circulation of the cable (3) passes between the two side walls (12a, 12b), pulley (1) characterized in that at least the first side wall (12a) can move according to the axis of circulation of the cable (3) and because the displacement of the blocker (12) between the first position and the second position corresponds to a displacement of the first side wall (12a) according to the second direction to move the first and second side walls (12a, 12b) along the axis of circulation of the cable (3) and lock the pulley (1) on the cable (3) by eccentric mechanism. 2. Pulley (1) according to claim 1, wherein the blocker (12) is freely mounted in a direction perpendicular to the axis of circulation of the cable (3) and perpendicular to the axes of rotation of the sheaves (2). , so that the weight of the blocker (12) drags one of the side walls (12a, 12b) of the slot (13) or the bottom wall towards the axis of circulation of the cable (3). 3. Pulley (1) according to claim 2, wherein the blocker (12) is arranged so that the weight of the blocker (12) brings the bottom wall and the circulation axis of the cable (3) closer. 4. Pulley (1) according to any of the preceding claims, wherein the first and second side walls (12a, 12b) are mounted so that they can move according to the axis of circulation of the cable (3), when the blocker (12 ) moves from the first position to the second position, the displacement distance of the first side wall (12a) is greater than the displacement distance of the second distance according to the axis of circulation of the cable (3). 5. Pulley (1) according to any of the preceding claims, configured to cooperate with a cable (3) of a first diameter and in which the separation distance between the first and second side walls (12a, 12b) is greater than the first diameter at least at a height greater than half the first diameter so that the first and second side walls (12a, 12b) are separated by a diameter of the cable (3) in the first position and in the second position. 6. Pulley (1) according to any of the preceding claims, which includes a box (14) that houses the blocker (12), such that the box (14) defines stops (15a, 15b) that limit the displacement of the first wall side (12a) and the second side wall (12b) according to the axis of circulation of the cable (3) in the first direction. 7. Pulley (1) according to the preceding claim, wherein the box (14) and the blocker (12) define a functional clearance according to a direction that passes through the two side walls (12a, 12b) of the groove (13). and the cable circulation axis (3). 8. Pulley (1) according to any of claims 6 and 7, wherein the box (14) and the blocker (12) define a functional clearance according to a direction that passes through the bottom wall and the axis of circulation of the cable (3). 9. Pulley (1) according to any of claims 6 to 8, wherein the blocker (12) is removably mounted with respect to the housing (14). 10. Pulley (1) according to any of claims 6 to 9, wherein the box (14) prevents the rotation of the blocker (12) around an axis of rotation parallel to the axes of rotation of the sheaves (2). 11. Pulley (1) according to any of claims 6 to 10, wherein the box (14) is mounted so that it cannot move with respect to a support bracket (5) on which the sheaves (2) rest. ) when the blocker (12) moves between the first and second positions. 12. Pulley (1) according to any of claims 6 to 11, wherein the box (14) is removably mounted with respect to a support bracket (5) on which the sheaves (2) rest. 13. Pulley (1) according to any of claims 6 to 12, wherein the box (14) defines first and second stops (15a, 15c) that limit the displacement of the first side wall (12a) of the blocker (12) according to the axis of circulation of the cable (3) and second and fourth stops (15b, 15d) that limit the displacement of the second side wall (12b) of the blocker (12) according to the axis of circulation of the cable (3), being the distance between the second and fourth stops (15b, 15d) less than the distance between the first and second stops (15a, 15c) according to the axis of circulation of the cable (3). 14. Pulley (1) according to any of claims 6 to 13, wherein the box (14) defines first and second stops (15a, 15b) configured to form a support plane of the blocker (12) in the first perpendicular position to the circulation axis. 15. Pulley (1) according to any of claims 6 to 11, wherein the box (14) defines a cavity that cooperates with a rotation axis (17) mounted on the blocker (12), so that the cavity and The axis of rotation imposes a rotation of the blocker (12) when the blocker (12) locks the pulley (1) on the cable (3) by an eccentric mechanism.