Spreader bar for distributing lifting points on a fragile load.

Abstract

The invention relates to a spreader bar 1 in which a longitudinal beam (2) comprises upper pulleys 11 and lower pulleys 12 suspended from this beam, a cable running between the upper and lower pulleys, and at least one upper or lower balancing device comprising a pair of adjacent pulleys, respectively upper or lower, and a spreader 20 for maintaining a distance between the respective axes X11, X12 of the pulleys of this lower pair. Figure 2 illustrates this in the abstract.

Description

Title of the invention: Lifting beam for distributing gripping points on a fragile load.

[0001] The invention lies in the field of lifting devices, in particular lifting beams.

[0002] Certain parts to be lifted, when they have a fragile structure, require numerous lifting points, in order to distribute the lifting stresses; this is particularly the case for lifting a part such as a slab, more particularly a pre-slab or a hollow core slab.

[0003] Such a part generally has very large horizontal dimensions for a small thickness. To avoid bending and breaking it under lifting forces, it is therefore necessary to distribute these forces. A cable spreader is generally used to handle this part while ensuring that the forces applied to each anchor in the part are identical and allows the use of more than 4 anchors.

[0004] Known cable spreaders comprise a metal structure, equally distributed pulleys and hooks for engaging with the anchors of the part to be handled, several hooks being mounted along the same cable and each being carried by a pulley movable along this cable.

[0005] When handling the part by this type of spreader, the cable is stretched and the tension of the cable is balanced on either side of each pulley. To achieve this balance, each pulley moves on the cable relative to the respective anchor point. Thus, the corresponding hook applies a horizontal force to its respective anchor.

[0006] When the lifting beam is tensioned and then lifted, the movement of the pulleys creates a movement of the part and / or an overload in the anchors, which can be dangerous for a handler or damaging to the part. In addition, free movement of the pulleys on the cable and of the cable relative to the structure can allow the part to tilt, in particular if one end is heavier than the other, which can also be dangerous for a handler or damaging to the part; it can also make it difficult to position the part if it is not in the required position.

[0007] A cable lifter is therefore more particularly suited to lifting flat and regular parts with a center of gravity centered on the part and anchor points distributed equidistantly; this is particularly the case for slabs, pre-slabs and hollow core slabs.

[0008] An aim of the invention is to propose a spreader bar which allows one to benefit from the advantages of a cable spreader bar without having the disadvantages.

[0009] According to the invention, a lifting beam comprises at least one longitudinal beam, a set of high pulleys distributed longitudinally along the beam and suspended from this beam, a cable mounted suspended from the high pulleys, and a set of low pulleys mounted rolling on said cable, each low pulley comprising a grip for anchoring a part to be lifted and at least one high balancing device or one low balancing device,

[0010] a low balancing device comprising: - a low pair of low pulleys adjacent to each other; - a high pulley, arranged between the pulleys of the pair; and, - a spacer to maintain a gap between the respective axes of the pulleys of the low pair,

[0011] the cable circulating from top to bottom to a first pulley of the low pair, then being returned from bottom to top by this first pulley, to the high pulley then being returned from top to bottom from this high pulley towards the second pulley of the low pair, which returns the cable upwards;

[0012] a high balancing device comprising: - a high pair of high pulleys adjacent to each other; and, - a spacer to maintain a spacing between the respective axes of the pulleys of the high pair,

[0013] the cable running from bottom to top to a first pulley of the high pair then being returned horizontally towards the second pulley of the high pair, then from top to bottom from this second high pulley.

[0014] The upper balancing device may further comprise two lower pulleys arranged on either side of the upper pair, the cable circulating from top to bottom to a first of the lower pulleys then being returned from bottom to top by this first lower pulley, to the first pulley of the upper pair then being returned horizontally towards the second pulley of the upper pair, then from top to bottom from this second upper pulley towards the second lower pulley, which returns the cable upwards.

[0015] The lifting beam may also comprise at least one triangulation bracing device comprising a hanger and a diagonal, the hanger extending substantially vertically downwards from the longitudinal beam, the diagonal connecting a lower end of the hanger to an attachment point on the longitudinal beam distant from the hanger, and a hook being fixed to the hanger to engage the part to be lifted.

[0016] Preferably, the hanger extends from one end of the longitudinal beam, the attachment point of the diagonal being near the middle of this beam.

[0017] Advantageously, the hanger and the diagonal are flexible linear elements, of preferably chains or cables.

[0018] Embodiments and variants will be described below, by way of non-limiting examples, with reference to the appended drawings in which:

[0019] [Fig-1] schematically represents a three-quarter perspective and top view of a spreader according to the invention;

[0020] [Fig.2] is a side elevational view of the spreader bar of [Fig.l];

[0021] [Fig.3] is a cross-sectional elevation view of a high balancing system of the rudder of [Fig.l]; and,

[0022] [Fig.4] is a cross-sectional elevation view of a low-level balancing system of the rudder of [Fig.l].

[0023] In particular, the terms "top", "bottom", "upper" and "lower", "horizontal" and "vertical", "left" and "right" and other terms of the same type may be arbitrarily used in the present description and generally refer to the positions illustrated in the figures.

[0024] [Fig. 1] illustrates a spreader bar 1 according to the invention. This spreader bar is substantially symmetrical relative to a first plane PI, vertical and longitudinal, and to a second plane P2, vertical transverse, these planes PI, P2 being perpendicular to each other.

[0025] The spreader comprises a substantially rigid structure 1-5 composed of two longitudinal beams 2, two transverse beams 3 and a support beam 4, itself longitudinal. It further comprises two spacers 5.

[0026] The recovery beam 4 extends substantially along the first plane PL. It comprises a lifting ring 7. The lifting ring is provided for fixing a hook of a lifting device, not shown; this lifting device may, for example, be a crane or an overhead crane. The ring 7 is arranged so that when the spreader is lifted empty, that is to say without any part being attached to it, the beams 2, 3 are substantially horizontal.

[0027] Each transverse beam 3 rests in its middle at a respective end of the recovery beam 4. Each transverse beam 3 comprises a specific end under which a respective longitudinal beam 2 is fixed; these ends are fixed on either side of the middle of the longitudinal beam, that is to say symmetrically on either side of the second plane P2, at a distance from the longitudinal ends 2E of this longitudinal beam.

[0028] Each spacer 5 is arranged transversely between the two longitudinal beams 2, between a respective end 2E of each longitudinal beam and a transverse beam 3. They limit the bending of the longitudinal beams in a horizontal plane.

[0029] We will now describe one of the longitudinal beams 2 and its equipment, in particular with reference to [Fig.2].

[0030] The beam 2 comprises longitudinal ribs 8 extending downwards. The spreader comprises a cable 10, high pulleys 11 and low pulleys 12. Each high pulley 11 is suspended from a rib 8 of the longitudinal beam 2 by a respective shackle 15. A hook 13 is fixed under each low pulley 12 by a respective shackle 15. Each end of the cable is fixed to a respective end 2E of the beam 2. It is operatively supported by the high pulleys 11 and operatively supports the low pulleys 12.

[0031] The high pulleys 11 have axes of rotation XI1, parallel to the transverse plane P2 and substantially coplanar with each other, in a horizontal plane. The base pulleys X12 have axes of rotation X12, parallel to the transverse plane P2 and substantially coplanar with each other, in a horizontal plane. The high pulleys, the cable and the low pulleys are arranged so that each hook 13 can be attached to a respective grip of a specific part to be lifted.

[0032] In the example illustrated, the spreader further comprises triangulation bracing devices 14. Each bracing comprises a hanger 16, here a chain, and a diagonal 17, here another chain. The hanger 16 extends substantially vertically downwards from a respective end 2E of the beam 2. A hook 18 is fixed to a lower end 19 of the hanger 16. The diagonal 17 connects the end 19 of the hanger 16 to a fixing point 21 on the longitudinal beam 2, close to its middle, here, below the nearest transverse beam 3. The hanger and the diagonal are not rigid, so as not to impose hyperstatic stresses on the part to be lifted. The bracing prevents a longitudinal offset of the part to be lifted relative to the spreader.

[0033] In the illustrated example, each longitudinal beam comprises 10 high pulleys 11. Among these ten high pulleys, 6 are coupled by pairs of neighboring pulleys 11A, 11B. [Fig.3] illustrates such a coupling. The coupling is achieved between two neighboring high pulleys by a spacer 20. Each longitudinal end of the spacer is articulated around the axis of rotation XI1 of a respective pulley of the pair of high pulleys 11A, 11B.

[0034] From left to right in [Fig. 3], a first strand 101A of the cable 10, coming from a respective low pulley, extends from the bottom upwards until it engages in the groove of a first pulley 1 1A of the pair. From right to left in [Fig. 3], a second strand 101B of the cable 10, coming from a respective low pulley, extends from the bottom upwards until it engages in the groove of the second pulley 1 1B of the pair. A third strand 101C horizontally connects the two first strands 101A, 101B together.

[0035] A high balancing device is thus formed. In fact, the spacer 20 maintains the spacing between the axes XI1 of the pulleys 1 IA, 1 IB, which tend to move closer together under the effect of opposing longitudinal forces exerted by the first strands 101A, 101B. Also, the angles A11A, A11B formed by the first strands 101A, 102B with the vertical are identical to each other (Al 1A=A1 IB). Thus, when the spreader is tensioned, then lifted, the upper pulleys 11 A, 1 IB of the pair do not move longitudinally. They remain suspended vertically from the longitudinal beam 2.

[0036] In the illustrated example, each longitudinal beam comprises eight low pulleys 11, each equipped with a hook 13. Among these eight low pulleys, 6 are coupled in pairs. [Fig.4] illustrates such a coupling. The coupling is achieved between two neighboring low pulleys by a spreader 20. Each longitudinal end of the spreader is articulated around the axis of rotation X12 of a respective pulley of the pair of low pulleys 12A, 12B.

[0037] From left to right in [Fig. 4], a first strand 102A of the cable 10, coming from a respective high pulley, extends from the top downwards until it engages in the groove of a first pulley 12A of the pair. From right to left in [Fig. 4], a second strand 102B of the cable 10, coming from a respective high pulley, extends from the top downwards until it engages in the groove of the second pulley 12B of the pair. A third strand 102C extends the first strand 102A, upwards and to the right, towards an intermediate high pulley 11, in which it engages. A fourth strand 102D extends the second strand 102B upwards and to the left towards the same intermediate high pulley 11, in which it engages, in the extension of the third strand.

[0038] A low balancing device is thus formed. In fact, the spacer 20 maintains the spacing between the axes X12 of the pulleys 12A, 12B; the angles A12A, A12B formed by the third and fourth strands 102C, 102D with the vertical are identical to each other (A12A=A12B). Thus, when the spreader beam is tensioned, then lifted, the upper pulleys 11A, 11B of the pair do not move longitudinally. They remain suspended vertically from the longitudinal beam 2.

[0039] The use of pairs (11A, 11B; 12A, 12B) of pulleys coupled together prevents longitudinal displacement of the pulleys, thus preventing movement of the part and / or overloading of the anchors of the part with which the hooks 13 are engaged. Such an arrangement therefore prevents displacement which could be dangerous for a handler or damaging to the part. Furthermore, throughout its handling by a lifting beam according to the invention, the part remains in a position required for its positioning, which is thus facilitated.

[0040] Of course, the invention is not limited to the examples which have just been described. On the contrary, the invention is defined by the claims which follow.

[0041] It will indeed appear to those skilled in the art that various modifications can be made to the embodiments described above, in the light of the teaching which has just been disclosed to him.

[0042] Thus, a coupled pair of low pulleys can be connected to a pair of intermediate high pulleys, themselves coupled, instead of being connected to only one intermediate pulley.

Claims

Claims

1. Lifting beam (1) characterized in that it comprises at least one longitudinal beam (2), a set of high pulleys (11) distributed longitudinally along said beam and suspended from this beam, a cable (10) mounted suspended from the high pulleys, and, a set of low pulleys (12) mounted rolling on said cable, each low pulley comprising a socket (13) for anchoring a part to be lifted and at least one high balancing device or a low balancing device, a low balancing device comprising: - a low pair (12A, 12B) of low pulleys adjacent to each other; - an intermediate high pulley (11), arranged between the pulleys of said pair;and, - a spreader (20) for maintaining a spacing between respective axes (XI2) of the pulleys of said low pair, said cable circulating from top to bottom to a first pulley (12A) of the low pair, then being returned from bottom to top by said first pulley, to the intermediate high pulley then being returned from top to bottom to the second pulley (12B) of the low pair, which returns said cable upwards; a high balancing device comprising: - a high pair (1 IA, 1 IB) of high pulleys adjacent to each other; and, - a spreader (20) for maintaining a spacing between the respective axes (XI1) of the pulleys of said high pair, the cable circulating from bottom to top to a first pulley (1 IA) of the high pair then being returned horizontally to the second pulley (1 IB) of the high pair, then from top to bottom from said second high pulley.;

2. A spreader according to claim 1, characterized in that the upper balancing device further comprises two lower pulleys (12), arranged on either side of the upper pair, the cable circulating from top to bottom to a first of said lower pulleys then being returned from bottom to top by this first lower pulley, to the first pulley of the upper pair then being returned horizontally towards the second pulley of the upper pair, then from top to bottom from this second upper pulley towards the second lower pulley, which returns the cable upwards.

3. A lifting beam according to one of claims 1 and 2, characterized in that it comprises at least one triangulation bracing device comprising a hanger (16) and a diagonal (17), said hanger (16) extending substantially vertically downwards from the longitudinal beam (2), said diagonal (17) connecting a lower end (19) of the hanger (16) to a fixing point (21) on the longitudinal beam (2) distant from the hanger, and, a hook (18) being fixed to the hanger to engage with the part to be lifted.

4. A spreader according to claim 3; characterized in that the hanger extends from one end (2E) of the longitudinal beam, the attachment point (21) of the diagonal being close to the middle of said longitudinal beam.

5. Lifting beam according to one of claims 3 and 4, characterized in that the hanger and the diagonal are flexible linear elements, preferably chains or cables.

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