SPREADER FOR DISTRIBUTING GRIPPING POINTS ON A FRAGILE LOAD

Description

[0001] The invention relates to the field of load lifting devices, in particular lifting beams.

[0002] Some loads, when they have a fragile structure, require numerous lifting points in order to distribute the lifting stresses; this is particularly the case, in the field of building construction, for the lifting of a pre-slab, whose thickness is small compared to its other dimensions. Multiple gripping points are distributed over the pre-slab. To equalize the forces on each gripping point, a lifting beam is used, comprising a continuous cable passing through pulleys between each gripping point. This system nevertheless has the following limitations and disadvantages: it assumes that there are gripping points at regular intervals; good symmetry of the load is required if it is to be able to maintain its horizontality; and it is very unstable to horizontal forces.

[0003] A lifting beam, such as that just described, is not particularly suitable for lifting building modules, for example so-called "site" bungalows. Such modules have variable dimensions; their structure is formed of metal profiles, in particular posts, which alone are capable of absorbing the lifting forces. The length of such a bungalow can vary as well as the number of posts distributed along this length; typically, for each longitudinal wall, there is a post at each end and one or two intermediate posts, connected by horizontal crosspieces.

[0004] US 1931931A discloses a spreader according to the preamble of claim 1.

[0005] An object of the invention is to provide a lifting beam that allows fragile loads to be lifted while minimizing the bending moments applied to them, while ensuring good stability, particularly if horizontal forces are applied to the load. Advantageously, such a lifting beam is suitable for lifting most known bungalows, whether they have one or two intermediate posts.

[0006] According to the invention, a spreader beam for lifting a load comprises a primary structure comprising two transversely spaced longitudinal beams, each beam carrying two longitudinally spaced balance beams, each balance beam being rotatably articulated about a transverse balance beam axis carried by the beam, and means for engaging a lifting point of the load. Preferably, the engaging means comprise at least one sling extending downwardly from each balance beam.

[0007] The spreader bar preferably comprises rigid connection means between a balance beam of one beam and a balance beam of the other beam, these balance beams rotating around the same balance beam axis.

[0008] According to the invention, each balance beam comprises a beam, mounted to rotate around the balance beam axis, a longitudinal beam arranged under the beam, and hangers, preferably two hangers, for fixing said beam to said beam. Advantageously, the beam, the beam and the hangers form, together and under load, a trapezoid. Preferably, each beam carries at least a third beam.

[0009] The suspension lines can be flexible, such as chains, cables, or straps. They can also be metal bars.

[0010] The at least one sling can be mounted fixed or longitudinally movable on the spreader beam, if necessary on the beam of the spreader beam.

[0011] The rigid connecting means between two balance beams may comprise at least one cross member, preferably two cross members, connecting the beams of the balance beams, each cross member being able to comprise anchors for fixing the hangers thereto. Each cross member may extend beyond each beam and comprise an anchor in the vicinity of each of its free ends, and, preferably, other anchors between them.

[0012] The spreader beam may also comprise coupling means for connecting two spreaders of the same beam together. Where appropriate, the coupling means are provided for holding two beams of the same beam in line with one another, in an isostatic manner, said coupling means preferably being of the Gerber type.

[0013] Embodiments and variants will be described below, by way of non-limiting examples, with reference to the appended drawings in which: [ Fig. 1 ] schematically represents a three-quarter perspective and top view of a spreader according to the invention; [ Fig. 2 ] is a cross-sectional view, in elevation, of the spreader bar of the figure 1 ; [ Fig. 3 ] is a longitudinal elevation view of the rudder of the figure 1 , in a first configuration; [ Fig. 4 ] is a longitudinal elevation view of the rudder of the figure 1 , in a second configuration; [ Fig. 5 ] is a longitudinal elevation view of a balance beam for the rudder bar of the figure 1 ; [ Fig. 6 ] a longitudinal elevation view of a device used in the configuration of the figure 4 , to connect two balance beams of the rudder bar of the figure 1 ; [ Fig. 7 ] is a top view of the device of the figure 6 ; [ Fig. 8 ] is a longitudinal elevation diagram illustrating the lifting of a load, in the configuration of the figure 3 ; And, [ Fig. 9 ] is a longitudinal elevation diagram illustrating the lifting of a load, in the configuration of the figure 4 .

[0014] There figure 1 illustrates a spreader bar 1 according to the invention. This spreader bar is substantially symmetrical relative to a longitudinal vertical plane P1 and to a transverse vertical plane P2, perpendicular to each other.

[0015] The spreader comprises a primary structure 2. The primary structure comprises two longitudinal beams 3, parallel to each other, and a spacing device 4 which keeps the beams rigidly separated and braced. The primary structure 2 is intended to be suspended from a lifting device (not shown), for example an overhead crane, by means of four slings each connecting a respective end of one of the beams 2 with a single lifting ring 7.

[0016] To figures 1 à 5 , the spreader bar is represented and described as it is when suspended from a lifting device, empty, that is to say without a load being attached to the spreader bar.

[0017] The spreader 1 further comprises four balance beams 10. Each beam 3 carries two balance beams 10, each arranged in the vicinity of a respective end of this beam.

[0018] Each balance is substantially symmetrical relative to a vertical transverse plane P10. As particularly illustrated in the figure 5 , each balance beam 10 comprises a beam 11, a beam 12 and two hangers 13, the two hangers connecting the beam to the balance beam. The 11 beam is mounted in rotation around a balance beam axis X10, horizontal, transverse and fixed relative to a respective beam 3.

[0019] Seen in projection in the plane of the figure 5 , the beam, the hangers and the beam together form a trapezoid whose small base is formed by the beam and the large base by the beam, each hanger connecting one end of the small base with a respective end of the large base. Thus, under the effect of the traction exerted by the beam on the hangers, or by any other load which would be added to it, the balance 10 is a substantially non-deformable assembly 11-13.

[0020] Each beam 11 of a beam 3 is arranged symmetrically to a respective beam of the other beam 3, relative to the longitudinal plane of symmetry P1. These two symmetrical beams share the same balance axis X10. They are rigidly connected to each other by a bracing device which comprises two horizontal and transverse crosspieces 14. Thus paired, these two balances 10 form a rigid tilting assembly 100. In the example illustrated, anchors 15 are arranged on each crosspiece 14 to fix the hangers 13 there, in a removable manner.

[0021] The spreader further comprises slings 16 extending freely from each beam 12. Each sling comprises, at a free end, a hook provided for releasably engaging a load. In the illustrated example, several fasteners 18 are arranged along each beam at fixed locations defined according to loads intended to be lifted with the spreader; each sling is releasably attached to a respective fastener 18.

[0022] In the example illustrated, each crosspiece 15 extends beyond each of the beams, relative to the longitudinal plane of symmetry P1. In addition, each crosspiece comprises, at each of its ends, an anchor 15, so that the spreader beam can lift a load whose width is significantly greater than the spacing between the two beams 2. Also, each crosspiece 14 comprises, on either side of each of the beams, two other anchors 15, for other, narrower load widths.

[0023] In the example illustrated, in addition to the end beams 11, the spreader bar 1 comprises two other pairs of internal beams 11B, closer to the transverse plane of symmetry P2. figures 1 à 3 And 5 , no beam is suspended therefrom. To use these internal beams 11B, it is necessary to detach together the hangers and the beams which equip the end beams 11, to equip the internal beams with the same beams 12, or with others, as illustrated in figure 4 . Thus, the spreader beam allows you to lift loads of varying length, depending on whether you use the end beams or the internal beams.

[0024] There figure 3 illustrates a first configuration of the spreader bar, in which the end beams 11 are used to form the balance beams 10. As illustrated in figure 8 , this first configuration allows, for example, to lift a bungalow 21 equipped with eight lifting points 22, four of which are arranged on each longitudinal side and visible at the figure 8 .

[0025] There figure 4 illustrates a second configuration of the spreader bar, in which the inner beams 11 are used to form the balance beams 10. As illustrated in figure 9 , this second configuration allows, for example, to lift a bungalow 21, shorter than that of the figure 8 . The bungalow in this example is equipped with six lifting points 22, three of which are arranged on each longitudinal side and visible at the figure 9 . One of the beams, on the right in the figure, is therefore only fixed to a single lifting point. To balance the balancers, the beams 12 of the same beam 3 are assembled so as to be kept in line with each other.

[0026] To assemble the beams 12 together, a coupling 25 is used which avoids creating a hyperstatic beam. In the example illustrated in figures 6 And 7 , the coupling is of the “Gerber” type which allows rotation around a transverse axis X1 and relative longitudinal translation of the beams. The coupling 25 comprises a yoke 26 and a slider 27. The yoke is fixed to one end of one of the beams 12 to be assembled, on the right at figures 6 And 7 ; the slider is fixed to one end of the other beam 12, on the left at figures 6 And 7 The slider and the yoke are provided so that the slider can slide in the yoke, in a substantially adjusted manner, parallel to the longitudinal plane of symmetry P1. The slider carries a pivot 28 defining a transverse coupling axis X25, fixed relative to the slider 27. A longitudinally oblong passage 29 is formed in the yoke 26. The pivot 28 is mounted through the passage.

[0027] Of course, the invention is not limited to the examples just described. On the contrary, the invention is defined by the claims which follow.

[0028] It will indeed appear to those skilled in the art that various modifications can be made to the embodiments described above, in light of the teaching which has just been disclosed to them.

[0029] Thus, instead of the slings being fixed to fixed locations, a sling may include means for sliding along its respective beam, in order to adapt its position to a given load. The beam may include notches, in order to maintain the sling in a chosen longitudinal position.

Claims

1. Lifting beam (1) for lifting a load (21), having a primary structure (2) comprising two transversely spaced-apart longitudinal beams (3), each longitudinal beam carrying two longitudinally spaced-apart balancers (10), each balancer (10) being rotatably articulated about a transverse balancer axis (X10) carried by said longitudinal beam, and, gripping means (16), preferably comprising at least one sling (16) extending downwards from each balancer, said gripping means (16) being adapted to engage a lifting point (22) of the load, characterized in that each longitudinal beam comprises a swing (11) mounted for rotation about the balancer axis (X10), a longitudinal girder (12) disposed beneath said swing, and hangers for securing said girder to said swing.

2. Lifting beam (1) according to claim 1, characterized in that it comprises rigid connecting means (14) between a balancer (10) of one longitudinal beam (3) and a balancer (10) of the other beam (3), said balancers rotating about the same balancer axis (X10).

3. Lifting beam (1) according to claim 1 or 2, characterized in that each balancer comprises two hangers, preferably, the swing, the girder and hangers together forming a trapezoid when under load.

4. Lifting beam (1) according to one of claims 2 and 3, characterized in that each longitudinal beam comprises at least a third swing (11B).

5. Lifting beam (1) according to claim 2 and one of claims 3 and 4, characterized in that the rigid connection means between two balancers comprise at least one cross-member (14), preferably two cross-members, connecting the swings (11) of said balancers, each cross-member preferably comprising anchors (15) for securing suspenders (16) thereto.

6. Lifting beam (1) according to claim 5, characterized in that each cross-member extends beyond each swing and comprises an anchor in the vicinity of each of its free ends, and preferably, other anchors between them.

7. Lifting beam (1) according to one of claims 1 to 6, characterized in that it comprises coupling means (25) for holding two girders (12) of a same longitudinal beam (3) isostatically in line with each other, said coupling means preferably being of the Gerber type.