Method of lifting a load and associated lifting device

Abstract

The invention relates to a method for lifting a load (4) by means of a lifting device (1) comprising a body (2) including a base (2a) and two side walls (2b), said lifting device (1) comprising, for each side wall (2b), at least one lifting means (3), said lifting device (1) being able to assume at least one loading position, in which said body (2) is unfolded and forms a flat surface, and at least one lifting position, in which said body (2) is folded so that each side wall (2b) forms an angle with said base (2a) to create an open loading volume for receiving said load (4). Figure for the abstract: Fig 5

Description

Title of the invention: Method for lifting a load and associated lifting device Technical field

[0001] The present invention is in the field of handling. It relates more particularly to a method for lifting a load and the associated lifting device. The invention makes it possible in particular to carry out lifting from above (craning) of a large load in a safe manner, by means of a light and compact device. Prior art

[0002] In the field of handling, particularly on construction sites, it is commonly necessary to lift loads from above, which is carried out by a lifting device such as a crane. In order to carry out this lifting, it is necessary to associate with the load lifting means such as one or more lifting rings or loops, flexible or rigid, compatible with the lifting device, for example with the hook of a crane.

[0003] For certain loads, particularly concrete, loops can be used anchored directly in the load by a specific anchoring means, lifting cables can be linked to these loops. Document EP0688922 presents a solution of this type. These arrangements, specially designed for concrete loads, are not compatible with all types of load.

[0004] Certain loads must be placed in packaging comprising a lifting means at its upper end, for example a metal crate, or a lifting net. These solutions have limited dimensions, and cannot accommodate loads having a dimension significantly greater than the other two.

[0005] For large loads, it is possible to use transport cradles. Transport cradles allow for safe lifting from above. However, they have the disadvantages of being heavy, which poses problems for their transport and use, and bulky, which poses problems for their storage. These disadvantages are aggravated by the fact that existing transport cradles are designed to be reused; they must therefore be stored or transported permanently and occupy dead volumes which are expensive. Statement of the invention

[0006] The present invention aims to overcome these drawbacks by proposing a lifting device which can be placed in the unfolded position, for loading, and in the folded position, for lifting, the lifting device being light, taking up very little space when not in use, and being able to be made from easily recyclable materials.

[0007] For this purpose, the invention relates to a method for lifting a load by means of a lifting device comprising a body comprising a base of substantially rectangular shape, and two side walls, extending from two opposite sides of the rectangle formed by said base, said body being made at least partly of a flexible material, said lifting device comprising, for each side wall, at least one lifting means fixed to one of its ends opposite to said base, said lifting device being able to adopt at least one loading position, in which said body is deployed and forms a flat surface, and at least one lifting position, in which said body is folded so that each side wall forms an angle with said base so as to form an open loading volume for receiving said load comprising the following steps: - placing said lifting device in the loading position,

[0008] - depositing a charge on said base, at least one dimension of said charge being greater than the length and width of the rectangle formed by said base, said load extending on either side of said base, the space above the side walls being left free, - placing said lifting device in the lifting position by lifting the side walls, - lifting said load by means of said lifting means.

[0009] Thanks to these provisions, a load of which one dimension is particularly larger than the other two can be easily placed in a lifting device and then lifted, in a safe, simple and rapid manner, the lifting device being simple to manufacture, light, easily transportable and storable, and able to be made from recyclable materials.

[0010] Said base and said side walls can be manufactured in one piece, which simplifies the manufacture of the lifting device.

[0011] Said side walls may have a substantially rectangular shape, which allows the lifting device to be well adapted to loads whose envelope has side faces of substantially rectangular shapes, which is common in particular in the field of construction.

[0012] In the loading position, said body can form a substantially rectangular flat surface of width equal to that of the base and of length equal to the sum of those of the base and the two side walls, which allows the lifting device to be well adapted to loads whose envelope has side faces and a base of substantially rectangular shapes, which is common in particular in the field of construction.

[0013] Said lifting device may comprise at least two longitudinal reinforcing strips fixed on two opposite sides of the rectangle formed by said body, each longitudinal reinforcing strip running along the base and said side walls, which makes it possible to reinforce the lifting device for loads having a certain weight.

[0014] Said lifting device may comprise at least four lifting means, each of the four lifting means being able to be fixed to one of the corners of the rectangle formed by said body, which makes it possible to lift the load in a stable and secure manner.

[0015] Said longitudinal reinforcing strips may have a length greater than that of said body and extend on either side of said body, and said lifting means may be formed in one piece with said longitudinal reinforcing strips, which is a simple means of producing a reinforced lifting device, allowing safe lifting of heavy loads.

[0016] Said lifting device may comprise a central reinforcing strip running substantially along a median of the rectangle formed by said body, and crossing said base and said side walls, which further reinforces the solidity of the lifting device, for lifting particularly heavy loads.

[0017] Each lifting means may comprise a loop configured to cooperate with a lifting hook of a lifting device, which is a simple and robust means of implementing the invention, compatible with most existing lifting devices.

[0018] At least one of said side walls may comprise two openings, and when said lifting device is in the lifting position, said openings may be arranged to allow the passage of the forks of a forklift, which makes it possible, in addition to lifting from above, such as craning, to allow lifting from below, such as stacking, offering significant flexibility in the use of the lifting device for transporting loads on a construction site.

[0019] Said lifting device may comprise at least one pair of straps, each strap of said pair extending from an edge of one of said side walls, and a means for attaching said pair of straps, the straps of said pair being configured to be able to be attached to each other parallel to the length of said base when said lifting device is in the lifting position and to hinder said load, thereby forming at least one lateral holding means in one of the directions not covered by the side walls.

[0020] Said lifting device may comprise at least two pairs of straps, a first pair of straps in which each strap of said pair extends from one edge of one of said side walls, and a second pair of straps in which each strap of said pair extends from the opposite edge of one of said side walls, and a means for attaching each pair of straps, the straps of each pair being configured to be able to be attached to each other parallel to the length of said base when said lifting device is in the lifting position and to hinder said load on two separate areas, thereby forming a means of lateral support in each of the directions not covered by the side walls.

[0021] The present invention also relates to a lifting device configured to implement a lifting method according to the invention.

[0022] Thanks to these provisions, a load of which one dimension is particularly larger than the other two can be easily placed in a lifting device and then lifted, in a safe, simple and rapid manner, the lifting device being simple to manufacture, light, easily transportable and storable, and able to be made from recyclable materials. Brief description of the drawings

[0023] The present invention and its advantages will appear better in the following description of several embodiments given as non-limiting examples, with reference to the appended drawings, in which:

[0024] [Fig-1] [Fig.l] is a top view of a lifting device according to the invention, at empty and in loading position,

[0025] [Fig.2] [Fig.2] is a perspective view of the lifting device of [Fig.l], loaded and in lifting position,

[0026] [Fig.3] [Fig.3] is a perspective view of the lifting device of [Fig.2], ready to be lifted with a first lifting device from below,

[0027] [Fig.4] [Fig.4] is a perspective view of the lifting device of [Fig.l], in lifting position, lifted by a second lifting device from above,

[0028] [Fig.5] [Fig.5] is a perspective view of the lifting device of [Fig.l], in lifting position, lifted by a third lifting device from above. Description of the embodiments

[0029] In the illustrated embodiments, identical elements or parts bear the same reference numbers. Furthermore, terms which have a relative meaning, such as vertical, horizontal, right, left, front, rear, above, below, etc. must be interpreted under normal conditions of use of the invention, and as shown in the figures. Furthermore, the geometric positions indicated in the description and the claims, such as “perpendicular”, “parallel”, “symmetrical” are not limited to the strict sense defined in geometry, but extend to geometric positions which are close, that is to say which accept a certain tolerance in the technical field considered, without influence on the result obtained. This tolerance is notably introduced by the adverb “substantially”, without this term necessarily being repeated before each adjective.

[0030] With reference to the figures, the lifting method according to the invention is carried out by means of a lifting device 1 comprising a body 2 mainly made at least in part of a flexible material, that is to say a material which can be folded and refolded fa smoothly, without breaking or damaging. This material can be, for example, a textile such as a polypropylene fabric. It can also be a fabric or a textile reinforced with fibers, such as glass fibers, aramid fabric, carbon, or even nylon.

[0031] The body 2 comprises a base 2a, of substantially rectangular shape, and two side walls 2b, extending from two opposite sides of the rectangle formed by the base 2a.

[0032] Each side wall 2b comprises at least one lifting means 3 fixed to one of its ends opposite the base 2a. The lifting means may be a rigid ring, for example metallic, or a flexible loop made of a textile material.

[0033] The lifting device 1 can adopt at least two positions: a loading position, and a lifting position.

[0034] In its loading position, as illustrated for example in [Fig. 1], the body 2 is unfolded, deployed and forms a flat surface. It can then be placed on the ground, and it is easy to place a load 4 there at the base 2a, with a view to lifting it.

[0035] Any type of load 4 can be lifted by a lifting device 1 according to the invention, and in particular loads having a larger dimension than the other two, or sets of one or more elements having a larger dimension than the other two. These elements can be metal profiles of various sections, for any type of use in the field of construction. The load 4 can for example be a set of waiting boxes, as illustrated in [Fig.2] to 5.

[0036] In its lifting position, as illustrated for example in [Fig. 2] to 4, the body 2 is folded so that each side wall 2b is raised and forms an angle with the base 2a, forming an open loading volume. This angle is for example less than or equal to 90°. To move from the loading position to the lifting position, the side walls 2b can be raised, for example using the lifting means 3, until they form walls which can be vertical, or inclined towards the inside of the lifting device 1, while the base 2a can remain flat on the ground. During lifting, the lifting device 1 is lifted by means of the lifting means 3, and rises above the ground. The load 4 then rests on the base 2a, and is held laterally by the two side walls 2b.

[0037] The material of the body 2 being flexible, during lifting, the base 2a may not remain flat and take the shape of the load 4. In this case the base 2a also participates in the lateral support of the load 4. In other embodiments, the load 4 comprises a rigid support whose dimensions are substantially identical to the dimensions of the base 2a, for example a transport pallet 5, and the base 2a retains a rectangular flat shape, the base 2a not participating in the lateral support of the load 4.

[0038] In the method according to the invention, the load 4 has at least one dimension greater than the length and width of the rectangle formed by the base 2a. This dimension is for example greater than 800 mm, preferably greater than 1000 mm. During a first deposition step, the load 4 is placed on the base 2a, which is preferably spread out on the ground. The load 4 protrudes on either side of the base 2a, leaving free the space located above the side walls 2b. During a second step, the side walls 2b are lifted by their ends opposite said base 2a until the lifting device 1 is in the lifting position. Then, the load 4 can be lifted with the lifting device 1 by means of the lifting means 3.

[0039] The base 2a has for example a length of between 800 and 1200 mm, for example 1030 mm, and a width of between 900 and 1300 mm, for example 1100 mm. The base 2a can have any other dimensions, depending on the dimensions of the load 4.

[0040] The side walls 2b are preferably both of the same dimensions, symmetrically with respect to the base 2a, and extend from the widths of the base 2a. In a preferred embodiment, the side walls 2b have a rectangular shape. The side walls 2b may for example have a length of between 800 and 1200 mm, for example 1030 mm, and a width of between 900 and 1300 mm, for example 1100 mm. The side walls 2b may have any other dimension, depending on the dimensions of the load 4.

[0041] The body 2 formed by the base 2a and the side walls 2b is preferably manufactured in one piece.

[0042] In the preferred embodiment illustrated in [Fig.l], when in the loading position, the body 2 of the lifting device 1 forms a flat surface of substantially rectangular shape, of width equal to that of the base 2a and the side walls 2b, and of length equal to the sum of the lengths of the base 2a and the side walls 2b. The body 2 is thus particularly easy to manufacture, especially when it is made in one piece.

[0043] The lifting device 1 preferably comprises four lifting means 3, each located for example at a corner of the rectangle formed by the body 2 when the lifting device 1 is in the loading position.

[0044] In order to improve the mechanical strength of the lifting device 1, the latter may comprise at least two longitudinal reinforcing strips 6a. The longitudinal reinforcing strips 6a are fixed on two opposite sides of the rectangle formed by the body 2, and each run along the base 2a and the two side walls 2b. The longitudinal reinforcing strips 6a may be made of the same material as the rest of the body 2, or of a more mechanically resistant textile material. Preferably, the body 2 further comprises two transverse reinforcing strips 6b fixed on the other two opposite sides of the rectangle formed by the body 2, that is to say for each side wall 2b, at its side opposite the base 2a. The transverse reinforcing strips 6b can be made by a layer of weaving. The lifting device 1 can also comprise a central reinforcing strip 6c, parallel and located at an equal distance from the longitudinal reinforcing strips 6a.

[0045] The longitudinal reinforcing strips 6a may have a length greater than the length of the body 2, extend on either side of the body 2, and be formed in one piece with the lifting means 3. The lifting means 3 may then take the form of loops 3 made of a textile material, the loops 3 being able to cooperate with a hook 7 of a lifting device such as a crane, as illustrated in [Fig. 5], or with a fork as illustrated in [Fig. 4]. In a preferred embodiment, the length of the extension of the longitudinal reinforcing strips 6a outside the body 2 is such that when lifting the load 4 at a point, as illustrated for example in [Fig. 5], the lifting angle 8 is between 55 and 65°, for example substantially 60°. The lifting angle 8 is illustrated in [Fig.5], and is equal to twice the angle of inclination of the portion of the longitudinal reinforcing strip 6a extending out of the body 2 relative to the vertical.Such a value of the lifting angle 8 allows optimal stability of the lifted load during its transport, and thus better safety. The length of the extension of the longitudinal reinforcing strips 6a outside the body 2 is for example between 1000 and 1500 mm, for example 1250 mm for a body 2 of length 3090 mm and width 1100 mm.

[0046] In a preferred variant of the invention, at least one of the side walls 2b, preferably both side walls 2b, comprise two openings 9. The openings 9 have a placement and dimensions adapted so that when the lifting device 1 is on the ground and in the lifting position, the forks of a forklift can pass through the openings 9. The openings 9 therefore have substantially identical dimensions, and are located at the same height when the lifting device 1 is on the ground and in the lifting position. Thus, if the load 4 is configured to be able to be moved by such a fork, for example if the load 4 comprises a transport pallet 5, the load 4 can be lifted from below while being arranged in the lifting device 1, as illustrated for example in [Fig. 3].

[0047] The openings 9 extend close to the boundary between the base 2a and the side wall 2b, for example from this boundary, and in the lifting position over a height of between 100 and 160 mm, for example 130 mm. The openings 9 may each extend over a width of between 450 and 500 mm, for example 475 mm. In a preferred embodiment, the openings 9 extend over the width of the side wall 2b from a first longitudinal reinforcing strip 6a to the central strip 6c, and from the central strip 6c to the second longitudinal reinforcing strip 6a.

[0048] The lifting device 1 may comprise at least one pair of straps 10. The straps 10 of the same pair each extend from one of the side walls 2b, and may be attached to each other by means of an attachment means (not shown) such as a ratchet tensioner, a hook-and-loop closure system, an adhesive or the like. When the lifting device 1 is on the ground in the lifting position and the straps 10 of the same pair are attached to each other, the straps 10 extend horizontally, parallel to the length of the base 2a, pass between or above the load 4, and therefore form a means for retaining said load 4 in one of the lateral directions which is not covered by the side walls 2b.

[0049] Preferably, the lifting device 1 comprises at least two pairs of straps 10 as described above, each pair of straps extending from one of the sides of the side walls 2b, so as to form means for retaining said load 4 in the two lateral directions which are not covered by the side walls 2b. The straps of two pairs located at the same level along the length of the side walls 2b may be made in one piece passing through the side wall 2b, as illustrated in [Fig.l].

[0050] In a preferred embodiment of the invention illustrated in [Fig.l], the lifting device 1 comprises at least six pairs of straps 10, for example ten pairs of straps 10, five on each side of the lifting device 1, distributed along the length of the side walls 2b on five different levels of the length.

[0051] When the load 4 consists of a plurality of elements, the straps 10 can be arranged between these elements. Depending on the shape of the elements, pinching zones of the straps can appear, which reinforces the holding of the load 4. The pinching zones are often horizontal, at the point where the elements rest on each other, but can also be vertical, if the elements are at least partially embedded in each other, which further reinforces the holding of the load 4 provided by the straps 10.

[0052] The load 4 may consist of a plurality of elongated elements such as waiting boxes. Such elements comprise an elongated portion of rectangular section, and reinforcements extending transversely, at regular intervals in the longitudinal direction, from this elongated portion. It is then possible to place the elements in this way: - installation of at least three first elements, so as to create a U with their elongated parts, the reinforcements being inside the U, - installation of a pair, preferably two pairs of straps above the U, - installation of at least one element, so as to close the U to form a rectangle, the reinforcements of the element being inside the rectangle. In this way, the straps 10 form stops for the frames, and oppose therefore to the lateral movement of the elements.

[0053] The present invention is of course not limited to the embodiments described but extends to any modification and variant obvious to a person skilled in the art within the limits of the appended claims. Furthermore, the technical characteristics of the different embodiments and variants mentioned above may be, in whole or in some cases, combined with each other.

Claims

Claims

1. A method of lifting a load (4) by means of a lifting device (1) comprising a body (2) comprising a base (2a) of substantially rectangular shape, and two side walls (2b), extending from two opposite sides of the rectangle formed by said base (2a), said body (2) being made at least partly of a flexible material, said lifting device (1) comprising, for each side wall (2b), at least one lifting means (3) fixed at one of its ends opposite to said base (2a), said lifting device (1) being able to adopt at least one loading position, in which said body (2) is deployed and forms a flat surface, and at least one lifting position,wherein said body (2) is folded so that each side wall (2b) forms an angle with said base (2a) so as to form an open loading volume for receiving said load (4) comprising the following steps: - placing said lifting device (1) in the loading position, - depositing a load (4) on said base (2a), at least one dimension of said load (4) being greater than the length and width of the rectangle formed by said base (2a), said load (4) extending on either side of said base (2a), the space above the side walls (2b) being left free, - placing said lifting device (1) in the lifting position by lifting the side walls (2b), - lifting said load (4) by means of said lifting means (3).,

2. A lifting method according to claim 1, wherein the base (2a) and the side walls (2b) are manufactured in one piece.

3. A lifting method according to one of claims 1 to 2, wherein said side walls (2b) have a substantially rectangular shape.

4. Lifting method according to one of claims 1 to 3, in which in the loading position, said body (2) forms a substantially rectangular flat surface of width equal to that of the base (2a) and of length equal to the sum of those of the base (2a) and of the two side walls (2b).

5. A lifting method according to claim 4, wherein said lifting device (1) comprises at least two longitudinal reinforcing strips (6a) fixed on two opposite sides of the rectangle formed by said body (2), each longitudinal reinforcing strip (6a) running along the base (2a) and said side walls (2b).

6. A lifting method according to one of claims 4 to 5, wherein said lifting device (1) comprises at least four lifting means (3), each of the four lifting means (3) being fixed to one of the corners of the rectangle formed by said body (2).

7. A lifting method according to claims 4 and 6, wherein said longitudinal reinforcing strips (6a) have a length greater than that of said body (2) and extend on either side of said body (2), and said lifting means (3) are formed in one piece with said longitudinal reinforcing strips (6a).

8. Lifting method according to one of claims 4 to 7, in which said lifting device (1) comprises a central reinforcing strip (6c) running substantially along a median of the rectangle formed by said body (2), and passing through said base (2a) and said side walls (2b).

9. Lifting method according to one of claims 1 to 8, in which each lifting means (3) comprises a loop configured to cooperate with a lifting hook (7) of a lifting machine.

10. A lifting method according to one of claims 1 to 9, wherein at least one of said side walls (2b) comprises two openings (9), and when said lifting device (1) is in the lifting position, said openings (9) are arranged to allow the passage of the forks of a forklift.

11. A lifting method according to one of claims 1 to 12, wherein said lifting device (1) comprises at least one pair of straps (10), each strap (10) of said pair extending from an edge of one of said side walls (2b), and means for attaching said pair of straps (10), the straps (10) of said pair being configured to be able to be attached to each other parallel to the length of said base (2a) when said lifting device is in the lifting position and to hinder said load (4).

12. A lifting method according to claim 11, wherein said lifting device (1) comprises at least two pairs of straps (10), a first pair of straps (10) in which each strap (10) of said pair extends from an edge of one of said side walls (2b), and a second pair of straps (10) in which each strap (10) of said pair extends from a second length of one of said side walls (2b), and means for attaching each pair of straps (10), the straps (10) of each pair of straps (10) being configured to be able to be attached to each other parallel to the length of said base (2a) when said lifting device (1) is in the lifting position and to hinder said load (4) on two separate zones.

13. Lifting device (1) configured to implement a lifting method according to one of claims 1 to 12.

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