FR3073215A1 - TELESCOPIC MAT GENRE LIFTING DEVICE FOR HIGH-LEVEL MANEUVERING OF AN OBJECT - Google Patents

Abstract

The invention relates to a lifting device (1) for maneuvering the height of an object, comprising a telescopic mast (2) whose upper end (21) is equipped with a support member (3) adapted to receive said object . The telescopic mast (2) comprises a fixed segment (5) and at least one movable segment (6) cooperating with translational maneuvering means (8). At least one movable segment (6) of rank "n" has a first end return member (65) around which a flexible transmission member (82) is folded to form a folded flexible transmission member (82) having two strands ( 821). The two strands (821) each comprise a free end (827) fixed to an anchor point (9) carried by a segment (5, 6) upstream of said telescopic mast (2); at least one of said strands (821) comprises at least one stop member (826). The mobile segment (6) of rank n comprises at least one stop (61) intended to cooperate with said at least one abutment member (826) of said folded flexible transmission member (82) in particular in case of rupture of one of said strands (821).

Description

Technical field to which the invention relates

The present invention relates, in general, to the field of tooling for construction work.

It relates more particularly to a lifting device of the kind with a telescopic mast, for maneuvering an object at height.

Technological background

Building work often requires lifting an object high.

This is for example the case of plates (in particular plasterboard) which must be fixed to the ceiling, on a wall or under crawlers in a room of the building.

Such manipulation is advantageously carried out by means of a lifting device, commonly known as a "plate lifter", which makes it easier to lift and then to maintain height during fixing.

For this, this lifting device comprises a telescopic mast, an upper end of which is equipped with a support member adapted to receive the object to be lifted.

This telescopic mast includes several segments:

- a fixed, lower segment, carried by a movable base, and

- At least one mobile segment, cooperating with means for operating in translation.

The translational maneuvering means conventionally include:

- a winch carried by the above-mentioned fixed segment, and

- At least one flexible transmission member, generally a metal cable, which cooperates with said at least one movable segment to ensure its operation in translation.

The lifting device is generally equipped with safety means which are intended to prevent sudden folding of the telescopic mast in the event of rupture of its flexible transmission member.

However, current security means are generally relatively technically complex and / or are not entirely effective.

Because of these difficulties, many lifting devices are devoid of security; operators are then faced with significant security problems.

Object of the invention

In order to remedy the aforementioned drawback of the state of the art, the present invention provides a lifting device for maneuvering an object at height, which lifting device comprises a telescopic mast, an upper end of which is equipped with a support member adapted to receive said object.

The telescopic mast includes several segments:

- a fixed, lower segment, carried by a movable base, and

- At least one mobile segment, cooperating with means for operating in translation.

The segments are defined by an increasing rank, starting from said fixed segment.

The means for operating in translation include:

- a winch carried by said fixed segment, and

- At least one flexible transmission member which cooperates with said at least one movable segment to ensure its operation in translation.

And according to the invention, at least one mobile segment of rank "n" comprises a first end deflection member around which said at least one flexible transmission member is folded back to form a folded flexible transmission member.

The folded flexible transmission member has two strands, extending on either side of said first terminal return member.

The two strands each have a free end fixed to an anchoring point carried by an upstream segment of said telescopic mast whose rank is less than said row n.

At least one of said two strands comprises at least one stop member.

And said mobile row n segment comprises at least one stopper intended to cooperate with said at least one stop member of said flexible transmission member folded in particular in the event of one of said strands breaking.

In this lifting device, the folded flexible transmission member thus ensures the translational maneuver of said at least one mobile segment associated with it.

In the event of a break in one of the strands of this folded flexible transmission member, said at least one stop member fitted to the other “intact” strand is intended to cooperate with at least one stopper of the movable segment of rank n supra.

This stop mechanism then ensures the retention of said at least one movable segment in its deployed position which is applied to it via the operating means.

It is then possible to retract the telescopic mast safely, with a view to replacing the damaged folded flexible transmission member.

It is even possible to continue using the telescopic mast, even if it is not optimal in terms of safety.

According to a particular embodiment, the first end deflection member consists of a first pulley which is carried at the level of a lower end of a front wall of said movable segment of rank n. The first pulley has an axis of rotation oriented parallel to said front wall.

Preferably, the front wall of said movable segment of rank n comprises a window at the level of which said first pulley is formed; said window is crossed by a first strand of said folded flexible transmission member, defining an inner portion and an outer portion on either side of said window; and said inner portion is equipped with said stop member intended to cooperate with said front wall forming a stopper.

More preferably, the front wall of said movable segment of rank n comprises at least a second pulley which is situated above said first pulley and facing the window; which at least a second pulley defines two grooves: - a first groove intended to cooperate with said first strand of said folded flexible transmission member, to participate in defining its inner and outer portions, and - a second groove, intended to cooperate with said second strand of said flexible transmission member folded back, to define a lower portion and an upper portion on either side of said at least one second pulley; and said lower portion of said second strand is equipped with said stop member.

Still according to the invention, the winch advantageously comprises two compartments which are each provided with one of said anchoring points and which are each suitable for winding one of the strands of said folded flexible transmission member, the speeds d 'winding within the two compartments being identical with respect to each other.

Preferably, said at least one upstream segment comprises at least one intermediate deflection member which cooperates with the two strands of said folded flexible transmission member, to participate in the translational maneuver of said at least one movable segment through said transmission member flexible folded.

In this case, said mobile segment of rank "n" can consist of an initial mobile segment, guided directly in translation within said fixed segment, and in that said at least one upstream segment corresponds to said fixed segment.

Alternatively, said mobile segment of rank "n" consists of a final mobile segment, carrying said support member; and said at least one upstream segment comprises said fixed segment and possibly at least one mobile segment, to ensure an operation in translation of said at least one mobile segment by means of a single folded flexible transmission member.

Still according to the invention, the telescopic mast advantageously comprises at least two mobile segments; a movable segment of rank n, greater than or equal to 3, comprises the first end return member cooperating with said flexible folded transmission member; the free ends of said folded flexible transmission member are fixed to anchor points carried by a n-2 row segment; and a movable segment of rank n-1 comprises at least one intermediate deflection member which cooperates with the two strands of said folded flexible transmission member to ensure the operation in translation of said movable segment of rank n by means of said folded flexible transmission member .

Where appropriate, said at least one intermediate deflection member consists of at least one pulley which defines two grooves and which is carried by a front wall of said upstream segment, which at least one pulley has an axis of rotation oriented parallel to said front wall .

Other non-limiting and advantageous characteristics of the lifting device according to the invention, taken individually or in any technically possible combination, are the following:

- the winch is chosen from manual or motorized winches;

- the support member consists of a support antenna for plasterboard;

- Said at least one flexible transmission member is chosen from metal cables, straps, belts or chains;

- Said stop member consists of a sleeve-shaped member, attached to said folded flexible transmission member.

The invention also provides a flexible transmission member for a lifting device according to the invention, comprising two free ends each intended to be fixed to an anchor point of said lifting device, and comprising at least one stop member intended to cooperate with a retainer of said lifting device.

Detailed description of an exemplary embodiment

The description which follows with reference to the appended drawings, given by way of nonlimiting examples, will make it clear what the invention consists of and how it can be carried out.

In the accompanying drawings:

- Figure 1 is a general perspective view of a lifting device according to the invention;

- Figure 2 shows the telescopic mast of the lifting device according to Figure 1, with a transverse vertical section plane, in which each movable segment is associated with its own flexible folded transmission member;

- Figure 3 shows a movable segment of the lifting device according to Figure 1, which is associated with its flexible transmission member;

- Figures 4 and 5 are partial and enlarged views of the movable segment of Figure 3, respectively in perspective and from the side, which show the arrangement of its lower pulleys;

- Figure 6 is a partial and enlarged view of the front wall of the movable segment of Figure 3, without the lower pulleys, showing the shape of its "lower" window;

- Figure 7 shows, side view, the initial mobile segment which is guided directly in translation within the fixed segment and whose flexible transmission member is connected to the winch;

- Figure 8 shows, in perspective view, the winch of Figure 7;

- Figure 9 shows, side view, a mobile segment which is guided in translation within another mobile segment and which is associated with its own flexible transmission member;

- Figure 10 shows another telescopic mast according to the invention, in a transverse vertical section plane, in which the movable segments are associated with a common flexible transmission member.

Lifting device

FIG. 1 represents, in general, a lifting device 1 according to the invention which is suitable for the maneuvering at height of an object (not shown) during a construction site within a building.

In general, the lifting device 1 comprises a telescopic mast 2, an upper end 21 of which is equipped with a support member 3 adapted to receive the aforementioned object.

The object in question advantageously consists of a plate, or even a plasterboard.

In this case, the lifting device 1 consists of a plate lifter which is useful for laying a plate on the ceiling, on a wall or under crawlers.

The support member 3 then advantageously consists of a support antenna for the plate. This support member 3 is formed here of an assembly of bars / side rails 31 which are arranged to form a plane for receiving the plate. This support member 3 is advantageously pivotable along a horizontal axis of rotation, to assist in fixing the plate to the ceiling, crawling or wall.

As shown in FIGS. 1 and 2, the telescopic mast 2 comprises several segments 5, 6:

a fixed segment 5, lower, carried by a movable base 7, and

- At least one movable segment 6, cooperating with translational maneuvering means 8 to control their translational maneuver between two end of travel positions (a folded / retracted configuration and a deployed configuration).

The translational maneuvering means 8 include:

a winch 81 carried by the fixed segment 5, and

- At least one flexible transmission member 82 which cooperates with said at least one movable segment 6 to ensure its operation in translation.

The winch 81 is advantageously chosen from manual winches (with a crank for setting in rotation) or motorized winches (with a driving member, for example electric, for setting into rotation).

Said at least one flexible transmission member 82 is advantageously chosen from metal cables, straps, belts or chains.

Each segment 5, 6 of the telescopic mast 2 advantageously consists of a profile made of metal.

Each segment 5, 6 comprises in particular several longitudinal walls (see in particular FIG. 2), defining a square or rectangular section, namely:

a front wall 51, 61, located opposite the winch 81,

a rear wall 52, 62, opposite said front wall 51, 61, and

- two side walls 53, 63, facing each other.

The front wall 51, 61 of the segments 5, 6 has two opposite ends: a lower end 511, 611 and an upper end 512, 612.

The front wall 51, 61 of the segments 5, 6 also has two opposite faces (FIGS. 3 to 5 and 7):

a front face 515, 615, located opposite the winch 81, and

- a rear face 516, 616, opposite said front face 515, 615.

There are two mobile segments 6 mentioned above (see in particular FIG. 2), namely:

an initial mobile segment 6a, guided directly in translation within the fixed segment 5, and

- A final mobile segment 6b which carries the upper end 21 equipped with the support member 3, guided in translation within the initial mobile segment 6a.

In a conventional manner per se, the fixed segment 5 and the initial mobile segment 6a thus each form a sort of sheath, ensuring respectively the guiding in translation of the initial mobile segment 6a and of the final mobile segment 6b.

For the sake of discussion of the invention, the segments 5, 6 are further defined by a rank (integer starting from 1) whose value is increasing (incrementing by 1) starting from the fixed segment 5 (rank with initial value 1) .

In this case, the segments 5, 6 of the telescopic mast 3 are defined by the following rows:

the fixed segment 5 has a rank of value 1,

the initial mobile segment 6a has a rank of value 2, and

- the final mobile segment 6b has a rank of value 3.

FIGS. 3 to 5 show in more detail a movable segment 6 of rank "n >> (n being greater than or equal to 2) which is coupled to its flexible transmission member 82.

The mobile segment 6 shown in these Figures 3 to 5 corresponds to the initial mobile segment 6a (rank 2); however, the other mobile segment (s) 6 (in this case the final mobile segment 6b of rank 3) advantageously have an identical or at least similar general structure.

Thus, according to the invention, the front wall 61 of the movable segment 6 of rank “n” comprises, at its lower end 611, lower end-return members 65, 66, which are arranged / arranged opposite a window 67 for cooperating with the associated flexible transmission member 82.

In particular, this movable segment 6 of rank "n" comprises a first end return member 65 around which the flexible transmission member 82 is folded back to form a flexible transmission member called "folded back" (designated by the same reference digital 82).

The first end deflection member 65 consists of a first pulley which is disposed at the level of the front wall 61 of the movable segment 6 of rank n, at its lower end 611.

The first pulley 65 has an axis of rotation 65 ’which is oriented parallel to this front wall 61.

This first pulley 65 has a single groove 651 (FIG. 4), intended to receive the folded flexible transmission member 82.

As subsequently developed, on either side of this first terminal return member 65, the folded flexible transmission member 82 then has two strands 821.

The movable segment 6 of rank "n" also includes a second end deflection member 66, overlying said first end deflection member 65 and intended to cooperate with the two strands 821 of the folded flexible transmission member 82.

The second end deflection member 66 consists of a second pulley which is disposed at the front wall 61 of the movable segment 6 of rank n, at its lower end 611.

The second pulley 66 has an axis of rotation 66 ′ oriented parallel to the front wall 61.

This second pulley 66 has two grooves (Figure 4):

a first groove 661 intended to cooperate with a first strand 8211 of the folded flexible transmission member 82, passing through the window 67 and extending on either side of the front wall 61, and

- A second groove 662, intended to cooperate with a second strand 8212 of this same folded flexible transmission member 821, which extends only opposite the front face 615 of the front wall 61.

Alternatively, not shown, the second end deflection member 66 consists of two second coaxial pulleys, each comprising one of the two grooves 661,662 mentioned above.

The two aforementioned pulleys 65, 66, forming the end deflection members, are arranged here so that their respective axes of rotation 65 ′, 66 ′ are set back with respect to the front wall 61, on the side of its rear face 616 .

These pulleys 65, 66 also extend partially through the window 67.

To this end, the window 67 has three portions (FIG. 6):

a lower portion 671, through which the first pulley 65 opens,

an upper portion 672, through which the second pulley 66 opens, and

- an intermediate portion 673, for the passage of the first strand 8211 mentioned above.

In the plane of this front wall 61:

the dimensions of the lower portion 671 correspond, apart from the clearance, to the section of the first pulley 65, and

- the dimensions of the upper portion 672 correspond, apart from play, to the section of the second pulley 66.

Such a dimensional ratio between the pulleys 65, 66 and the window 67 here allows the front wall 61 of the movable segment 6 of rank "n" to form a stop which is intended to cooperate, in the event of rupture of the member flexible transmission 82, with stop members 826 equipping the strands 821 of the latter.

In other words, the passage / space between a pulley 65, 66 and its window portion 671, 672 67 is dimensioned so as to allow the passage of the strands 821 while preventing possible passage of the stop members 826 equipping these same strands 821.

In this case, the two strands 821 each comprise at least one stop member 826.

Said at least one stop member 826 here consists of a sleeve-shaped member, advantageously cylindrical, the section of which is greater than the strands 821.

This stop member 826 is held in position on its strand 821, advantageously by clamping or crimping.

In particular, each strand 821 and said at least one associated stop member 826 must have a mechanical resistance which is greater than the combined weight of the movable segments 6 and of the object carried by the telescopic mast 2.

To ensure safety functionality, the folded flexible transmission member 82 is also suitably wound / reeled on the terminal return members 65, 66, with said one or said stop members 826 suitably distributed.

In this case, the first strand 8211 of the folded flexible transmission member 82 comprises two portions, extending on either side of the window 67, namely:

- an inner portion 8211a, extending within the movable segment 6 of rank n and between the two terminal return members 65, 66, and

- an outer portion 8211b, extending opposite the front face 615 of the front wall 61 and above the second end deflection member 66.

The first groove 661 of the second pulley 66 thus participates in defining the interior 8211a and exterior 8211b portions of this first strand 8211.

Each of these two portions 8211a, 8211b of the first strand 8211 is here equipped with a stop member 826 intended to cooperate with the front wall 61 forming a stop in the event of one of the strands 621 breaking.

In particular, the stop member 826 of the outer portion 8211b is located near the front wall 61. For example, the length of the outer portion 8211b between the front wall 61 and the stop member 826 is at most 10 cm.

In this case, the movable segment 6 also includes an intermediate member

617, of cylindrical shape and the peripheral surface of which is adjacent to the first pulley 65.

This intermediate member 617 intervenes advantageously for the maintenance of the flexible transmission member folded 82 in the groove 651 of the first pulley 65, and also as a retainer for the stop member 826 equipping the inner portion 8211a in the event of rupture.

Alternatively, not shown, the folded flexible transmission member 82 could here be equipped with a single stop member 826 on its inner portion 8211a of the first strand 8211.

The second strand 8212 of the folded flexible transmission member 82 also comprises two portions, extending on either side of the second groove 662 of the second pulley 66, namely:

a lower portion 8212a, located between the two end return members 65, 66, and

- an upper portion 8212b, extending opposite the front face 615 of the front wall 61 and above the second end deflection member 66.

The lower portion 8212a of this second strand 8212 is equipped here with one of the stop members 826 intended to cooperate with the front wall 61 forming a retainer.

To be complete, the outer portion 8211b of the first strand 8211 and the second strand 8212 extend here in a free space E which is preserved opposite the front face 615 of the front wall 61 of the movable segment 6 of rank n.

For this, this front wall 61 is here equipped with a shoe 618 (FIGS. 3 and

4) which is intended to cooperate with the rear face 516, 616 of the upstream segment 5, 6 of row n-1.

Furthermore, the two strands 821 of the folded flexible transmission member 82 each also have a free end 827 which is fixed to an anchor point 9 carried by an upstream segment 5, 6 of the telescopic mast 2.

By "upstream segment 5, 6" is meant a segment 5, 6 (fixed or mobile) of the telescopic mast 2 whose rank is less than said mobile segment 6 of rank "n".

Possible arrangements of these folded flexible transmission members 82, and their anchor points 9, are described below in relation to FIGS. 7 to 10.

First embodiment

According to a first embodiment shown in FIGS. 2 and 7 to 9, each mobile segment 6 is associated with its own flexible folded transmission member 82.

The first folded flexible transmission member 82a cooperates with the terminal return members 65, 66 of the initial movable segment 6a having rank 2 (Figures 7 and 8).

The two free ends 827 of this first folded flexible transmission member 82a are fixed to an “mobile” anchor point 9 which is carried by the fixed segment 5 of the telescopic mast 2.

In this case, this attachment to the fixed segment 5 is effected by means of the winch 81 which has two compartments 811.

Each compartment 811 is provided here with one of the anchoring points 9 and is suitable for winding one of the strands 821 of the folded flexible transmission member 82a.

This winch 81 is shaped so that the winding speeds within the two compartments 811 are identical with respect to each other.

For this purpose, for example, the compartments 811 have the same diameter; and a winch crank turn 81 produces the same number of turns for each of the two compartments 811.

In this configuration, the fixed segment 5 (n-1 row segment) comprises an intermediate return member 58 which cooperates with the two strands 821 of this first folded flexible transmission member 82a.

More precisely, the two strands 821 of this first folded flexible transmission member 82a follow the same path so as to form several successive sections, namely:

a first section extending between the winch 81 and the intermediate return member 58 of the fixed segment 5,

- A second section extending between the intermediate return member 58 of the fixed segment 5 and the terminal return members 65, 66 of the initial mobile segment 6a.

The second folded flexible transmission member 82b cooperates with the terminal return members 65, 66 of the final mobile segment 6b (row segment n having a value 3), to participate in the translational maneuver of this final mobile segment 6b (FIG. 9 ).

The two free ends 827 of this second folded flexible transmission member 82b are fixed to an anchor point 9 "fixed" carried by the upper end 512 of the wall 51 of the fixed segment 5 equipping the telescopic mast 2 (forming here the segment of rank n-2).

For this, each free end 827 is here folded back on itself to form a loop. And the anchor point 9 is formed by a transverse shaft added through said loops 827 and carried by the fixed segment 5.

The initial movable segment 6a (forming the segment of rank n-1) comprises an intermediate deflection member 68 which cooperates with the two strands 821 of this second folded flexible transmission member 82b.

The two strands 821 of this second folded flexible transmission member 82 follow the same route composed of several successive sections, namely:

a first section extending between the anchoring points 9 carried by the fixed segment 5 and the intermediate return member 68 of the initial mobile segment 6a, and

- A second section extending between the intermediate return member 68 of the initial mobile segment 6a and the terminal return members 65, 66 of the final mobile segment 6b.

In general, the various intermediate return members 58, 68 mentioned above are provided at the upper end 512, 612 of the upstream segment 5, 6a equipped.

The intermediate return members 58, 68 here each consist of a pulley which is provided with two grooves 583, 683 each intended to receive a strand 821 (only the grooves 683 are visible in FIG. 3).

The pulley 58, 68 is carried at the level of the front wall 51, 61 of the upstream segment 5, 6a concerned.

This pulley 58, 68 has an axis of rotation 58 ’, 68 ′ oriented parallel to this associated front wall 51, 61.

Alternatively, not shown, the intermediate return members 58, 68 consist of two pulleys, coaxial, each comprising one of the two grooves 583, 683 above.

In a variant not shown of this embodiment, the telescopic mast 2 could include:

a rack winch for the translational maneuver of the initial mobile segment 6a (in place of the first folded flexible transmission member 82a), and

the second folded flexible transmission member 82b cooperating, on the one hand, with the terminal return members 65, 66 of the final mobile segment 6b, and on the other hand, with the fixed segment 5, as described above in relationship to Figure 9.

Second embodiment

According to a second embodiment shown in FIG. 10, the mobile segments 6 can be associated with a single folded flexible transmission member 82.

The folded flexible transmission member 82 then cooperates with the terminal return members 65, 66 fitted to the final mobile segment 6b which carries the support member 3.

The two free ends 827 of this folded flexible transmission member 82 are fixed to an anchor point 9 "mobile" carried by the fixed segment 5 of the telescopic mast 2.

In this case, this attachment to the fixed segment 5 is effected by means of the winch 81 which comprises two compartments 811 identical to those described above in relation to FIGS. 7 to 9.

And the upstream members 5, 6a with respect to said final movable segment 6b comprise the intermediate return members 58, 68 which are suitably arranged to ensure the translational maneuver of the movable segments 6 by means of the flexible folded transmission member 82 .

In this regard :

the fixed segment 5 comprises an intermediate deflection member 58 at the level of the upper end 512 of its front wall 51, and

- The initial movable segment 6a comprises two intermediate deflection members 68, namely a lower intermediate deflection member 681 at the lower end 611 of its front wall 61 and an upper intermediate deflection member 682 at the end upper 612 of its front wall 61.

The aforementioned intermediate return members 58, 68 are identical to those described above in the first embodiment.

These intermediate return members 58, 68 each consist of a pulley which is provided with two grooves 583, 683 each intended to receive a strand 821 of the flexible folded transmission member 82.

The pulley 68 is carried at the level of the front wall 61 of the upstream segment 5, 6a concerned.

This pulley 68 has an axis of rotation oriented parallel to this associated front wall 51, 61.

Alternatively, not shown, the intermediate return members 58, 68 may consist of two pulleys, coaxial, each comprising one of the two grooves 583, 683 mentioned above.

The single folded flexible transmission member 82 is thus wound around the various intermediate return members 58, 68 to ensure the operation of the mobile segments 6 of the telescopic mast 2.

The two strands 821 of this single folded flexible transmission member 82 follow the same route composed of several successive sections, namely:

a first section extending between the winch 81 and the intermediate return member 58 of the fixed segment 5,

a second section extending between the intermediate return member 58 of the fixed segment 5 and the lower intermediate return member 68 of the initial mobile segment 6a,

a third section extending between the lower intermediate return member 68 of the initial mobile segment 6a and the upper intermediate return member 68 of this same initial mobile segment 6a,

- A fourth section extending between the upper intermediate return member 68 of the initial mobile segment 6a and the terminal return members 65, 66 of the final mobile segment 6b.

Use of the lifting device

The translational movement of said at least one mobile segment 6 is ensured by the control of the winch 81.

In this case, each folded flexible transmission member 82 is intended to be maneuvered so as to apply identical displacements (or at least almost identical) on each of its two strands 821.

In other words, in normal operation, each folded flexible transmission member 82 is intended to be fixed (without displacement in translation), or at least almost fixed, relative to the terminal return members 65, 66 associated.

The two strands 821 of the same folded flexible transmission member 82 then have identical lengths, or at least approximately identical lengths, one with respect to the other, throughout the operation of the associated movable segment or segments 6.

In the two abovementioned embodiments, the two free ends 827 of the folded flexible transmission member 82 are here fixed to an anchor point 9 carried by the winch 81.

The operation of the winch 81 then generates, as a function of the direction of rotation, a winding / unwinding of the strands 821 in their respective compartments 811.

This winding / unwinding maneuver is advantageously carried out at the same speed on each of the two strands 821 of the folded flexible transmission member 82.

The two strands 821 thus both remain at constant tension, exerting traction on the first lower terminal return member 65.

In particular, in the first embodiment (FIGS. 7 to 9), the deployment of the initial mobile segment 6a is carried out by traction on its end return members 65, 66.

This traction is obtained by winding the strands 821 of the folded flexible transmission member 82 in their respective compartments 811, which leads to a shortening of these two strands 821.

Still in this first embodiment, the deployment of the initial mobile segment 6a generates a simultaneous deployment of the final mobile segment 6b.

Indeed, the deployment of the initial movable segment 6a causes an upward translational movement of its upper intermediate return member 68, which results in an upward vertical pull on the end return members 65, 66 of the final mobile segment 6b via the second member flexible transmission 82b.

Furthermore, in the second embodiment (FIG. 10), the mobile segments 6 are deployed by traction via the folded flexible transmission member 82 on, on the one hand, the terminal return members 65, 66 of the final mobile segment 6b and, on the other hand, the lower intermediate return member 681 of the initial mobile segment 6a.

Again, this traction is obtained by winding the strands 821 of the folded flexible transmission member 82 in their respective compartments 811, which leads to a shortening of these two strands 821.

In general, the folding of the telescopic mast 2 (movement of said at least one movable segment 6 in a descending direction) is obtained by an operation in the opposite direction of said at least one folded flexible transmission member 82.

In practice, this return is obtained by unwinding the strands 821 of the folded flexible transmission member 82 from their respective compartments 811, which leads to an elongation of these two strands 821.

In operation, it is possible that one of the strands 821 of said at least one folded flexible transmission member 82 may break; this is particularly the case due to wear of this strand 821.

In this case, the movable segment or segments 6 of the telescopic mast 2 possibly undergo a short movement in a downward direction.

This movement is in all cases blocked when the stop member 826 equipping the strand 821 "intact" comes to rest on its retainer which is formed here by the front wall 61 of the movable segment 6 of row n above (or even by the 'insert 617).

Different situations are possible which depend on the breaking point of the folded flexible transmission member 82.

For example, in the event of rupture of the upper portion 8212b of the second strand 8212, a stop is obtained, on the one hand, of the stop member 826 equipping the lower portion 8212a of the second strand 8212, against the face before 615 of the front wall 61 and, on the other hand, of the stop member 826 equipping the inner portion 8211a of the first strand 8211, against the rear face 616 of the front wall 61 (or even by the intermediate member 617) .

Again, for example, in the event of the outer portion 8211b of the first strand 8211 breaking, abutment is obtained, on the one hand, of the stop member 826 equipping this outer portion 8211b, against the front face 615 of the front wall 61 and, on the other hand, the stop member 826 equipping the inner portion 8211a of the first strand 8211, against the rear face 616 of the front wall 61.

The strand 821 "intact" therefore ensures the maintenance of the deployment which is applied to the telescopic mast 2, without risk of complete and accidental folding of the latter.

It is possible to fold the telescopic mast 2 safely by maneuvering the strand 821 "intact", then replacing the damaged folded flexible transmission member 82.

Claims (11)

1. Lifting device for maneuvering an object at height, which lifting device (1) comprises a telescopic mast (2) of which an upper end (21) is equipped with a support member (3) adapted to receive said object, which telescopic mast (2) comprises several segments (5, 6): - a fixed, lower segment (5), carried by a movable base (7), and - At least one movable segment (6), cooperating with means for operating in translation (8), which segments (5, 6) are defined by an increasing rank, starting from said fixed segment (5), which means for operating in translation (8) include: - a winch (81) carried by said fixed segment (5), and - At least one flexible transmission member (82) which cooperates with said at least one movable segment (6) to ensure its maneuver in translation, characterized in that at least one movable segment (6) of rank "n" comprises a first end deflection member (65) around which said at least one flexible transmission member (82) is folded back to form a folded flexible transmission member (82), which folded flexible transmission member (82) has two strands (821 ), extending on either side of said first end deflection member (65), which two strands (821) each have a free end (827) fixed to an anchor point (9) carried by a segment ( 5, 6) upstream of said telescopic mast (2) whose row is less than said row n, in that at least one of said two strands (821) comprises at least one stop member (826), and in that said movable segment (6) of rank n comprises at least one retainer (61) intended to cooperate with said at least a stop member (826) of said folded flexible transmission member (82) especially in the event of one of said strands (821) breaking. 2. Lifting device according to claim 1, characterized in that the first end deflection member (65) consists of a first pulley which is carried at a lower end (611) of a front wall (61) of said movable segment (6) of rank n, which first pulley (65) has an axis of rotation (65 ') oriented parallel to said front wall (61). 3. Lifting device according to claim 2, characterized in that the front wall (61) of said movable segment (6) of rank n comprises a window (67) at the level of which said first pulley (65) is formed, and in that said window (67) is crossed by a first strand (8211) of said folded flexible transmission member (82), defining an inner portion (8211 a) and an outer portion (8211 b) on either side of said window (67), and in that said inner portion (8211a) is equipped with said stop member (826) intended to cooperate with said front wall (61) forming a stopper (61). 4. Lifting device, according to claim 3, characterized in that the front wall (61) of said movable segment (6) of rank n comprises at least a second pulley (66) which is located above said first pulley ( 65) and opposite the window (67), which at least a second pulley (66) defines two grooves (661, 662): a first groove (661) intended to cooperate with said first strand (8211) of said folded flexible transmission member (82), to participate in defining its inner (8211 a) and outer (8211 b) portions, and - a second groove (662), intended to cooperate with said second strand (8212) of said folded flexible transmission member (82), to define a lower portion (8212a) and an upper portion (8212b) on either side of said at least one second pulley (66), and in that said lower portion (8212a) of said second strand (8212) is equipped with said stop member (826). 5. Lifting device according to any one of claims 1 to 4, characterized in that the winch (81) has two compartments (811) which are each provided with one of said anchoring points (9) and which are each adapted to the winding of one of the strands (821) of said folded flexible transmission member (82), the winding speeds within the two compartments (811) being identical with respect to each other . 6. Lifting device according to claim 5, characterized in that said at least one upstream segment (5, 6) comprises at least one intermediate deflection member (58, 68) which cooperates with the two strands (821) of said member of folded flexible transmission (82), to participate in the translational operation of said at least one movable segment (6) by means of said folded flexible transmission member (82). 7. Lifting device according to claim 6, characterized in that said movable segment (6) of rank "n" consists of an initial movable segment (6a), guided directly in translation within said fixed segment (5), and in that said at least one upstream segment (5, 6) corresponds to said fixed segment (5). 8. Lifting device according to claim 6, characterized in that said movable segment (6) of rank "n" consists of a movable segment (6b) final, carrying said support member (3), and in that said at least one upstream segment (5, 6) comprises said fixed segment (5) and possibly at least one movable segment (6), to ensure an operation in translation of said at least one movable segment (6) by means of a member single folded flexible transmission (82). 9. Lifting device according to any one of claims 1 to 7, characterized in that the telescopic mast (2) comprises at least two mobile segments (6), in that a mobile segment (6) of rank n , greater than or equal to 3, comprises the first end deflection member (65) cooperating with said folded flexible transmission member (82), in that the free ends (827) of said folded flexible transmission member (82) are fixed to anchor points (9) carried by a segment (5, 6) of rank n-2, and in that a movable segment (6) of rank n-1 comprises at least one intermediate deflection member (68) which cooperates with the two strands (821) of said folded flexible transmission member (82) to ensure the translational maneuvering of said movable segment (6) of rank n by means of said folded flexible transmission member (82). 10. Lifting device according to any one of claims 6 to 9, characterized in that said at least one intermediate deflection member (58, 68) consists of at least one pulley which defines two grooves (583, 683) and which is carried at the level of the front wall (51, 61) of said upstream segment (5, 6), which at least one pulley (58, 68) has an axis of rotation (58 ', 68') oriented parallel to said wall before (51.61). 11. Flexible transmission member for a lifting device according to any one of claims 1 to 10, comprising two free ends (827) each intended to be fixed to an anchor point (9) of said lifting device (1), and comprising at least one stop member (826) intended to cooperate with a stopper (61) of said lifting device (1).