FR3128965A1 - HOPPER OBSTRUCTION DEVICE - Google Patents

Abstract

DEVICE FOR OBSTRUCTING A HOPPER Device for obstructing (1) a hopper in a slab of a building, comprising a substantially rectangular platform (2) comprising four sides (2a-2d) and an upper surface (3) substantially planar and continuous, extending lengthwise (L1) along a longitudinal direction (I-I) and extending widthwise (L2) along a transverse direction (II-II). The length (L1) and the width (L2) of the platform (2) are adjustable. A plurality of plates (4a, 4b, 5a-5d, 6a-6d), integral with the platform (2), are arranged overlapping one another so as to form between them said substantially flat and continuous upper surface (3) whatever the length (L1) and the width (L2) of the platform (2). Figure to be published with abstract: Fig. 3

Description

HOPPER OBSTRUCTION DEVICE

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of construction, and more particularly relates to a device for obstructing a hopper.

During the erection of a building, reservations are generally made in the successive slabs of said building for service shafts, stairs or elevator shafts.

These reservations, also called "hoppers", present a great danger for users who can fall on several floors.

It is also often necessary to obstruct the hoppers in order to be able to install formwork and thus allow the manufacture of vertical walls around the periphery of the hoppers.

It is therefore recommended or necessary to obstruct the hoppers. To do this, we know a device for obstructing a hopper as marketed by the French company COPAC. This known device comprises a substantially rectangular platform comprising four sides and a substantially planar and continuous upper surface, extending in length in a longitudinal direction and extending in width in a transverse direction. The platform is made by assembling wooden parts and panels.

Such a device must be made according to the measurements of the hopper to be clogged. However, there are no standard sizes for hoppers. The obstruction devices of a hopper must therefore be custom-made for a site, and are generally scrapped after said site.

A problem proposed by the present invention is to provide a device for obstructing a hopper which is reliable and can be easily reused from site to site.

To achieve these and other objects, the invention provides a device for obstructing a hopper in a slab of a building, comprising a substantially rectangular platform comprising four sides and a substantially planar and continuous upper surface, extending in length in a longitudinal direction and extending in width in a transverse direction; according to the present invention:
- the length of the platform in said longitudinal direction is adjustable between a minimum length and a maximum length,
- the width of the platform in said transverse direction is adjustable between a minimum width and a maximum width,
- A plurality of plates, secured to the platform, are arranged to overlap each other so as to form between them said substantially planar and continuous upper surface regardless of the length and width of the platform.

The size of the platform can thus be adjusted in its two longitudinal (length adjustment) and transverse (width adjustment) directions, and can thus be reused on several sites, even if the sizes of the hoppers vary from site to site. the other.

The overlapping plates allow the user to be secured so that he cannot pass through the obstruction device, regardless of the sizes (length and width) of the obstruction device.

Advantageously, it can be provided that:
- the length of the platform in said longitudinal direction is continuously adjustable between a minimum length and a maximum length, and/or
- the width of the platform in said transverse direction is continuously adjustable between a minimum width and a maximum width.

The obstruction device can thus be adapted in its dimensions so as to correspond as closely as possible to the size of the hopper to be obstructed.

Preferably, it can be provided that:
- the platform comprises a frame comprising four side crosspieces connected two by two to each other via four corner pieces,
- each side crosspiece is arranged to slide relative to two corner pieces, so that two corner pieces arranged to slide relative to the same side crosspiece can be selectively brought together or moved away from each other by sliding with respect to said side crosspiece.

The obstruction device thus has a reliable, simple and robust structure.

Advantageously, each side crosspiece can be connected by a sliding connection to a central platform structure, so as to be able to be selectively brought closer to or further away from said central platform structure by translation with respect to said central platform structure.

The platform of the obstruction device can thus be adapted very finely.

Preferably, it can be provided that:
- each side crosspiece is arranged to slide freely relative to two corner pieces,
- each side crosspiece is connected to the central platform structure by a helical connection.

The obstruction device thus has a structure that is reliable, robust, simple to manufacture and handle, and the helical connection ensures that the corresponding dimension (length or width) of the platform is maintained.

Advantageously, the platform may include:
- four side plates, each secured to a respective side crosspiece,
- four corner plates, each attached to a respective corner piece,
- a central plate, secured to the central platform structure.

Said plates can thus be placed overlapping one another in a fairly simple manner to provide a substantially flat and continuous upper surface, without risk of overlapping fault.

Preferably, the platform may comprise rolling means arranged under the platform and intended to bear against a flat surface such as the ground.

The rolling means make it easier to adjust the dimensions (length and width) of the obstruction device.

Advantageously, the platform may include support means arranged under the platform and intended to bear against a flat surface such as the ground, the support means being movable between:
- a retracted position, in which the platform can come to rest on a flat surface such as the ground via its rolling means,
- an extended position, in which the platform can come to rest on a flat surface such as the ground via its support means, said rolling means then being kept away from said flat surface such as floor.

The support means allow the obstruction device to be placed on a surface without the risk of the platform moving laterally by means of its rolling means. This is particularly important when transporting it by truck.

Preferably, the obstruction device may comprise, on each side of the platform, a plurality of rolling rollers rotating around axes of rotation parallel to said side. The rollers are arranged to be able to roll against the vertical walls located on the periphery of the hopper to avoid damaging the latter after their manufacture by shuttering.

Advantageously, the obstruction device may comprise lifting rings arranged at the four corners of the platform. Eyebolts facilitate the handling of the obstruction device by a crane to raise or lower it through successive slabs of the building being constructed.

To adapt to any hoppers of very large dimensions, the obstruction device may comprise, on each of its sides, means for coupling with another obstruction device.

Preferably, it can be provided that:
- the platform comprises, over at least part of the length of each of its sides, at least one side flap extending between a proximal end and a distal end, said at least one side flap being pivotally articulated along its proximal end in a direction parallel to said side,
- said at least one side flap is movable between a deployed position, in which said at least one side flap is substantially parallel to the upper surface of the platform by extending it radially, and a folded position, in which said at least one flap side is disposed substantially perpendicular to the upper surface of the platform with its distal end protruding above the upper surface of the platform.

The side flaps can thus be retracted (in the folded position) to allow the obstruction device to be moved vertically in a column by passing above or below supports projecting on the inner face of the walls of said column. . Said supports are intended to support the obstruction device by vertical support to obstruct a hopper.

Advantageously, the lifting rings and the side flaps can be connected by a mechanical connection shaped so that:
- the suspension of the platform by means of the lifting rings causes the side flaps to move towards their fallback position;
- In the absence of lifting force on the lifting rings, the side flaps are returned to their deployed position, preferably by the effect of gravity alone.

The arrangement of the shutters in the folded position is thus automatically obtained by suspension of the platform by means of the lifting rings. No additional operation is necessary, so that the risk of interference between the obstruction device and the supports projecting on the inside face of the column walls is effectively limited.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, characteristics and advantages of the present invention will emerge from the following description of particular embodiments, given in relation to the appended figures, among which:

There is a perspective view of a particular embodiment of an obstruction device according to the invention, said obstruction device having minimum dimensions in length and width;

There is a perspective view of the obstruction device of the , said obstruction device having a minimum length and a maximum width;

There is a perspective view of the obstruction device of the , said obstruction device having maximum dimensions in length and width;

There is an exploded perspective view of a plate assembly forming the top surface of the airway obstruction device ;

There is a schematic top view illustrating the structure of the obstruction device of the ;

There is a first perspective view of a corner piece used in the obstruction device of the ;

There is a second perspective view of the corner piece of the ;

There is a perspective view illustrating a central platform structure and side rails used in the obstruction device of the ;

There is a perspective view illustrating a central platform structure and a side rail used in the obstruction device of the ;

There is a perspective and cross-sectional view illustrating the assembly of the central platform structure and the side crosspiece of the ;

There is a partial side view of the obstruction device of the , with support means in the retracted position;

There is a partial side view of the obstruction device of the , with the support means in the extended position;

There is a partial view, in section and in perspective, of the obstruction device of the resting on a first type of support in a column;

There is a partial view, in section and in perspective, of the obstruction device of the intended to rest on a second type of support in a column;

There is a partial and perspective view of the obstruction device of the when it is suspended by suspension hooks; And

There is a partial view, in section and in perspective, of the obstruction device of the resting on the second type of supports in a column.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

When identical reference numerals are used in several figures, embodiments or variants of the invention, these reference numerals designate identical or similar elements in each of the figures, embodiments or variants.

In Figures 1 to 16 is illustrated a particular embodiment of obstruction device 1 according to the invention. This obstruction device 1 is intended to obstruct a hopper in a slab of a building under construction.

The obstruction device 1 comprises a substantially rectangular platform 2 comprising four sides 2a to 2d and a substantially planar and continuous upper surface 3, extending in length L1 in a longitudinal direction I-I and extending in width L2 in a transverse direction II-II.

The length L1 of the platform 2 in said longitudinal direction II is adjustable between a minimum length (FIGS. 1 and 2) and a maximum length ( ). The width L2 of the platform 2 in said transverse direction II-II is adjustable between a minimum width ( ) and a maximum width (Figures 2 and 3).

In other words, the platform 2 is extensible along its two dimensions (length L1 and width L2) between a fully folded position ( ) and a fully extended position ( ). Here, the platform 2 is square, in the fully folded position and in the fully extended position. It could however be rectangular in one and/or the other of these positions.

If the platform 2, even deployed to the maximum, remains too small compared to the hopper to be obstructed, it can be secured along one or more of its sides 2a to 2d to another platform 2 thanks to coupling means 25 provided on each of its sides 2a to 2d. In practice, the coupling means 25 comprise a plurality of holes 250 capable of receiving a securing bolt ( ).

We observe on the that a plurality of plates 4a and 4b (known as central plates), 5a to 5d (known as side plates) and 6a to 6d (known as corner plates), integral with platform 2, are arranged parallel and overlapping each other others so as to form between them said upper surface 3 substantially planar and continuous regardless of the length L1 and the width L2 of the platform 2.

In this overlapping, one observes more particularly using the that :
- Plates 4a and 4b overlap (above) plates 5a to 5d and 6a to 6d;
- Plates 5a to 5d overlap (above) plates 6a to 6d.

On the a diagram illustrating in a simplified manner the constitution of the platform 2 is shown.

The platform 2 comprises a frame 7 comprising four side crosspieces 8a to 8d connected in pairs to each other via four corner pieces 9a to 9d.

Each side crosspiece 8a to 8d is arranged to slide relative to two corner pieces 9a to 9d, so that two corner pieces 9a to 9d arranged to slide relative to the same side crosspiece 8a to 8d can be selectively brought together or separated from each other by sliding relative to said side crosspiece 8a to 8d. For example, the side crosspiece 8a is arranged to slide relative to the two corner pieces 9a and 9d, so that the two corner pieces 9a and 9d arranged to slide relative to the same side crosspiece 8a can be selectively brought closer or separated from each other by sliding relative to said side crosspiece 8a to 8d. To do this, sliding connections 10a to 10h are provided between the corner pieces 9a to 9d and the side crosspieces 8a to 8d.

It is also observed that each side crosspiece 8a to 8d is connected by a sliding connection 11a to 11d to a central platform structure 12, so as to be able to be selectively brought closer or further from said central platform structure 12 by translation relative to said structure central platform 12 (according to movements illustrated by the arrows 13a to 13d). For example, the side crosspiece 8a is connected by a translation connection 11a to the central platform structure 12, so as to be able to be selectively moved closer to or further from said central platform structure 12 by translation relative to said central platform structure 12 according to a movement illustrated by the arrow 13a.

More specifically:
- the sliding links 10a to 10h are freely sliding. Each side crosspiece 8a to 8d is thus arranged to slide freely relative to two corner pieces 9a to 9d;
- The translation connections 11a to 11d are helical. Each side crosspiece 8a to 8d is connected to the central platform structure 12 by a helical connection 11a, 11b, 11c or 11d.

The length L1 of the platform 2 in said longitudinal direction II is continuously adjustable between a minimum length L1 (FIGS. 1 and 2) and a maximum length L1 ( ), and the width L2 of the platform 2 in said transverse direction II-II is continuously adjustable between a minimum width L2 ( ) and a maximum width L2 (FIGS. 2 and 3).

The four side plates 5a to 5d are each secured to a respective side crosspiece 8a to 8d. For example, the side plate 5a is integral with the side crosspiece 8a.

For their part, the four corner plates 6a to 6d are each secured to a respective corner piece 9a to 9d. For example, the corner plate 6a is integral with the corner piece 9a.

Finally, the central plates 4a and 4b, forming a central plate 40, are integral with the central platform structure 12. Here, although the central plate 40 is formed by means of two central plates 4a and 4b, it could be formed by a single and unique plate, or by a greater number of plates.

Corner pieces 9a to 9d are shown in Figures 6 and 7 (taken from different viewing angles). They each comprise two primary tubes 14a and 14b forming between them a right angle, and two secondary tubes 15a and 15b forming between them a right angle and each parallel to a respective primary tube 14a or 14b.

The corner pieces 9a to 9d also include a roller 23 on each of their sides. The platform 2 is thus provided, on each of its sides 2a to 2d, with at least two rollers 23 rotating around axes of rotation parallel to said sides 2a to 2d.

The central platform structure 12 and the side crosspieces 8a to 8d are more particularly illustrated in the . Each side rail 8a to 8d comprises a primary side rail 16a and a secondary side rail 16b parallel to each other.

In practice, the primary 14a-14b and secondary 15a-15b tubes of the corner pieces 9a to 9d are intended to receive by freely sliding fitting the ends of the primary 16a and secondary 16b side crosspieces of the side crosspieces 8a to 8d. For example, the primary tubes 14a and 14b of the corner piece 9a receive by freely sliding fitting the ends of the primary side crosspieces 16a of the side crosspieces 8a to 8d, while the secondary tubes 15a and 15b of the corner piece 9a receive by freely sliding fitting the ends of the secondary side crosspieces 16b of the side crosspieces 8a to 8d.

On the the central platform structure 12 is shown with the single side crosspiece 8a for greater clarity. It can be seen that the central platform structure 12 is in the form of a cross formed by four tubes 12a to 12d. The tube 12a is received according to a sliding fit in a connecting tube 17 secured to the side crosspiece 8a.

We see more particularly on the that the tube 12a comprises, at its free end, a nut 18 which is captive and integral in rotation with the tube 12a. The nut 18 is engaged by screwing on a threaded rod 19 which extends inside the connecting tube 17 and which is integral in rotation with an operating head 20. The threaded rod 19 is immobile in translation in the connecting tube 17 and rotatably mounted relative to connecting tube 17. A helical sliding connection is thus formed between the central platform structure 12 and the side crosspiece 8a.

When a user rotates the operating head 20, he rotates the threaded rod 19 relative to the connecting tube and relative to the nut 18. Depending on the direction of rotation, the nut 18 moves on the threaded rod 19 and causes the tube 12a to slide in the connecting tube 17. By increasing the overlap of the tube 12a by the connecting tube 17, the side crosspiece 8a is brought closer to the central structure of the platform 12: the width is thus reduced. L2 of platform 2. By reducing the overlap of tube 12a by connecting tube 17, the side crosspiece 8a is moved away from the central structure of platform 12: the width L2 of platform 2 is thus increased.

An identical arrangement is provided between the tubes 12b to 12d and the side crosspieces 8b to 8d.

On the , we see that the platform 2 comprises rolling means 21 arranged under the platform 2 and intended to bear on a flat surface such as the ground S. In practice, the rolling means 21 comprise eight rollers 21a (two under each corner pieces 9a to 9d, see ). When a user wishes to adjust the dimensions of the platform 2, the latter rests on the ground S via the rolling means 21. Thus, when the user causes the displacement of one or more of the side crosspieces 8a at 8d, the platform 2 varies in size easily thanks to the rolling of the rollers 21a on the ground S. The rollers 21a are adjustable (free to pivot about respective axes perpendicular to the upper surface 3).

In Figures 11 and 12, it is also seen that the platform 2 comprises support means 22 arranged under the platform 2 and intended to bear against a flat surface such as the ground S. The support means 22 are movable between:
- a withdrawal position ( ), in which the platform 2 can bear on a flat surface such as the ground S via its rolling means 21,
- an extended position ( ), in which the platform 2 can come to rest on a flat surface such as the ground S via its support means 22, the said rolling means 21 then being kept away from the said flat surface such as the S ground.

In practice, the support means 22 comprise four feet 22a to 22d respectively arranged under the side crosspieces 8a to 8d ( ). The feet 22a to 22d are used in particular in the extended position to rest the obstruction device 1 stably on the trailer of a truck during its transport.

On the , we see that the obstruction device 1 comprises lifting rings 24 arranged at the four corners of the platform 2. The lifting rings 24 are retractable in order to maintain a substantially flat and continuous upper surface 3: they are illustrated in the deployed position on the , and in the retracted position on the .

Still in figures 1, 6 and 15, we observe that:
- the platform 2 comprises, over the entire length of each of its sides 2a to 2d, a plurality of side flaps 26 extending between a proximal end 26a and a distal end 26b, said side flaps 26 being pivotally articulated according to their proximal end 26a in a direction parallel to said sides 2a to 2d,
- the side flaps 26 are movable (by means of hinges) between a deployed position (FIGS. 1 and 6), in which said side flaps are substantially parallel to the upper surface 3 of the platform 2, and a folded position ( ), wherein said side flaps are arranged substantially perpendicular to the upper surface 3 of the platform 2 with their distal end 26b projecting above the upper surface 3 of the platform 2.

The lifting rings 24 and the side flaps 26 are connected by a mechanical connection shaped so that:
- the suspension of the platform by means of the lifting rings 24 causes a displacement of the side flaps 26 towards their folded position thanks to the lifting cams 24a and 24b ( );
- in the absence of lifting force on the lifting rings 24, the side flaps 26 are returned to their deployed position ( and 6), preferably by gravity alone.

At the beginning of its use, the obstruction device 1 rests on the ground via its rolling means 21 and generally has minimum length L1 and width L2 (to reduce its size during transport). To adapt the obstruction device 1 to the dimensions of the hopper to be obstructed, the user rotates the operating heads 20 to cause the displacement of one or more side crosspieces away from the central platform structure 12. The plates 4a, 4b, 5a to 5d and 6a to 6d slide on each other by overlapping and retain a substantially flat and continuous upper surface 3.

Once the correct length L1 and width L2 have been reached, the obstruction device 1 is lifted by a crane by means of its lifting rings 24. When the obstruction device 1 is still at a low height from the ground, the support means 22 (feet 22a to 22d) are moved into the extended position.

The obstruction device 1 is then introduced ( ) by lowering into the hopper 27 to be blocked with a first floor slab 28, being lowered into a start of column 29 made by shuttering between the ground floor slab and the first floor slab 28.

The obstruction device 1 can then come to rest on supports 30 of a first type such as a flying fastener recoverable from the inside (AVRI) marketed by the company SATECO. The supports 30 of a first type are introduced from the outside of the column 29 through the walls 29a and 29c to form projections inside the column 29 at a suitable predetermined height. The obstruction device 1 is introduced by lowering into the hopper 27 until it comes to rest on the supports 30 of a first type. The upper surface 3 is then level with the upper surface of the slab 28 thanks to the arrangement at an adequate and predetermined height of the supports 30 of a first type.

Once in place in the hopper 27, the obstruction device 1 allows workers to walk safely on the slab 28 without falling into the hopper 27.

The obstruction device 1 can also serve as a support surface for laying formwork panels intended to form the side walls 29a' to 29c' extending the start of the column 29 between the first floor slab 28 and the second floor slab 28' (to form an elevator shaft over several floors, for example).

Once the new walls 29a′-29c′ have been manufactured between the first floor slab 28 and the second floor slab 28′, the obstruction device 1 can be raised by crane into the column 29 by means of the suspension rings 24 to coming to obstruct the hopper 27' of the second floor slab 28'. During this elevation by crane, the rollers 23 roll on the walls 29a'-29c' to guide the obstruction device 1 and limit the risk of damage to the walls 29a'-29c'.

To hold the obstruction device 1 in the hopper 27′, support 30′ of a second type is provided this time. Supports 30' of a second type are introduced from inside column 29 through walls 29a' and 29c' to form projections inside column 29 at a suitable predetermined height.

The supports 30' of a second type each have a base 31 respectively fixed to the walls 29a' and 29c', and a lever 32 hinged to pivot on the base 31 (double-arrow 33) between a vertical position ( ) and a horizontal position ( ). When the lever 31 is in the horizontal position, it forms a projection (away from the respective walls 29a' and 29c') on which the obstruction device 1 ( ).

To pass over supports 30' of a second type, the suspension of the obstruction device 1 via its lifting rings 24 causes the movement of the side flaps 26 towards their fallback position ( ). The lifting cams 24a and 24b hold the side flaps 26 in the folded position. The obstruction device 1 can thus be raised in the column 29 without interfering with the bases of the supports 30' of a second type. If the levers 32 are in the horizontal position, the obstruction device 1 pushes them back into the vertical position as it passes, then the levers 32 fall back (preferably by the sole effect of gravity) into the horizontal position so as to be able to receive supports obstruction device 1.

The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof contained within the scope of the claims below.

Claims (13)

Device for obstructing (1) a hopper (27, 27') in a slab (28, 28') of a building, comprising a substantially rectangular platform (2) comprising four sides (2a-2d) and a upper (3) substantially planar and continuous, extending in length (L1) in a longitudinal direction (II) and extending in width (L2) in a transverse direction (II-II), characterized in that:
- the length (L1) of the platform (2) in said longitudinal direction (II) is adjustable between a minimum length (L1) and a maximum length (L1),
- the width (L2) of the platform (2) in said transverse direction (II-II) is adjustable between a minimum width (L2) and a maximum width (L2),
- a plurality of plates (4a, 4b, 5a-5d, 6a-6d), integral with the platform (2), are arranged overlapping one another so as to form between them said upper surface (3) substantially planar and continues regardless of the length (L1) and the width (L2) of the platform (2). Obstruction device (1) according to Claim 1, characterized in that:
- the length (L1) of the platform (2) in said longitudinal direction (II) is continuously adjustable between a minimum length (L1) and a maximum length (L1), and/or
- the width (L2) of the platform (2) in said transverse direction (II-II) is continuously adjustable between a minimum width (L2) and a maximum width (L2). Obstruction device (1) according to one of Claims 1 or 2, characterized in that:
- the platform (2) comprises a frame (7) comprising four side crosspieces (8a-8d) connected two by two to each other via four corner pieces (9a-9d),
- each side crosspiece (8a-8d) is arranged to slide relative to two corner pieces (9a-9d), so that two corner pieces (9a-9d) arranged to slide relative to the same side crosspiece (8a-8d) can be selectively brought closer together or further apart by sliding relative to said side crosspiece (8a-8d). Obstruction device (1) according to Claim 3, characterized in that each lateral crosspiece (8a-8d) is connected by a sliding connection (11a-11d) to a central platform structure (12), so as to be able to be selectively moved towards or away from said central platform structure (12) by translation with respect to said central platform structure (12). Obstruction device (1) according to Claim 4, characterized in that:
- each side crosspiece (8a-8d) is arranged to slide freely relative to two corner pieces (9a-9d),
- each side crosspiece (8a-8d) is connected to the central platform structure (12) by a helical connection (11a-11d). Obstruction device (1) according to one of Claims 4 or 5, characterized in that the platform (2) comprises:
- four side plates (5a-5d), each secured to a respective side crosspiece (8a-8d),
- four corner plates (6a-6d), each secured to a respective corner piece (9a-9d),
- a central plate (4a, 4b), secured to the central platform structure (12). Obstruction device (1) according to any one of Claims 1 to 6, characterized in that the platform (2) comprises rolling means (21) arranged under the platform (2) and intended to bear on a flat surface such as the ground (S). Obstruction device (1) according to Claim 7, characterized in that the platform (2) comprises support means (22) arranged under the platform (2) and intended to bear against a flat surface such as the ground (S), the support means (22) being movable between:
- a retracted position, in which the platform (2) can come to rest on a flat surface such as the ground (S) via its rolling means (21),
- an extended position, in which the platform (2) can bear on a flat surface such as the ground (S) via its support means (22), said rolling means (21) being then kept away from said flat surface such as the ground (S). Obstruction device (1) according to any one of Claims 1 to 8, characterized in that it comprises, on each side of the platform (2), a plurality of running rollers (23) rotatable about axes of rotation parallel to said side (2a-2d). Obstruction device (1) according to any one of Claims 1 to 9, characterized in that it comprises, on each of its sides (2a-2d), coupling means (25) with another device for obstruction (1). Obstruction device (1) according to any one of Claims 1 to 10, characterized in that it comprises lifting rings (29) arranged at the four corners of the platform (2). Obstruction device (1) according to any one of Claims 1 to 11, characterized in that:
- the platform (2) comprises, over at least part of the length of each of its sides (2a-2d), at least one side flap (26) extending between a proximal end (26a) and a distal end ( 26b), said at least one side flap (26) being hinged to pivot along its proximal end (26a) in a direction parallel to said side (2a-2d),
- said at least one side flap (26) is movable between a deployed position, in which said at least one side flap (26) is substantially parallel to the upper surface (3) of the platform (2), and a folded position , wherein said at least one side flap (26) is arranged substantially perpendicular to the upper surface (3) of the platform (2) with its distal end (26b) protruding above the upper surface (3) of the platform (2). Obstruction device (1) according to Claims 11 and 12, characterized in that the lifting rings (24) and the side flaps (26) are connected by a mechanical connection shaped so that:
- the suspension of the platform (2) by means of the lifting rings (24) causes the side flaps (26) to move towards their folded position;
- In the absence of lifting force on the lifting rings (24), the side flaps (26) are returned to their deployed position, preferably by the effect of gravity alone.