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: Spreader beam for distributing gripping points on a fragile load.

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

[0002] Some parts to be lifted, when they have a fragile structure, require many lifting points in order to distribute the lifting stresses; This is particularly the case for the lifting of a part such as a slab, more particularly a precast slab or a hollow slab.

[0003] Such a part generally has very large horizontal dimensions for a small thickness. To avoid bending and breaking it under lifting forces, these forces must therefore be distributed. A cable lifting beam is generally used, which allows handling this part while ensuring that the forces applied to each anchor point in the part are identical and allows the use of more than four anchor points.

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

[0005] When the workpiece is handled by this type of lifting beam, the cable becomes taut and the cable tension equalizes on either side of each pulley. To achieve this equilibrium, each pulley moves along the cable relative to its respective anchor point. Thus, the corresponding hook applies a horizontal force to its respective anchor point.

[0006] During the tensioning of the lifting beam and subsequent lifting, the movement of the pulleys creates movement of the workpiece and / or an overload in the anchorages, which can be dangerous for a handler or damaging to the workpiece. Furthermore, free movement of the pulleys on the cable and of the cable relative to the structure can allow the workpiece to tip, particularly if one end is heavier than the other, which can also be dangerous for a handler or damaging to the workpiece; it can also make positioning the workpiece difficult if it is not in the required position.

[0007] A cable spreader 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 slabs.

[0008] One object of the invention is to provide a lifting beam which allows the advantages of a cable lifting beam to be enjoyed without the disadvantages.

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

[0010] a lower balancing device comprising: - a low pair of low pulleys close to each other; - a high pulley, positioned between the pulleys of the pair; and, - a spacer to maintain a distance between the respective axes of the pulleys of the lower pair,

[0011] the cable running from top to bottom to a first pulley of the lower pair, then being sent back from bottom to top by this first pulley, to the upper pulley and then being sent back from top to bottom from this upper pulley to the second pulley of the lower pair, which sends the cable back up;

[0012] a high balancing device comprising: - a high pair of pulleys placed close together; and, - a spreader to maintain a distance between the respective axes of the pulleys in the high pair,

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

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

[0015] The spreader beam may also include 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 a point of attachment on the longitudinal beam distant from the hanger, and a hook being attached to the hanger to engage with the part to be lifted.

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

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

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

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

[0020] [Fig.2] is a side view, in elevation, of the rudder post of [Fig.1];

[0021] [Fig.3] is a transverse elevation view, a high balancing system of the the spreader bar of [Fig. 1]; and,

[0022] [Fig.4] is a transverse elevation view, a low balancing system of the [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 used arbitrarily in this description and generally refer to the positions illustrated in the figures.

[0024] Figure 1 illustrates a rocker arm 1 according to the invention. This rocker arm is substantially symmetrical with respect to a first plane PI, vertical and longitudinal, and to a second plane P2, vertical and transverse, these planes PI and P2 being perpendicular to each other.

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

[0026] The support beam 4 extends substantially along the first plane PL. It includes a lifting ring 7. The lifting ring is designed to accommodate a hook for a lifting device, not shown; this lifting device could, for example, be a crane or an overhead crane. The ring 7 is positioned so that when the lifting beam is raised unloaded, i.e., without any part attached to it, the beams 2 and 3 are substantially horizontal.

[0027] Each transverse beam 3 rests at its midpoint at a respective end of the transfer beam 4. Each transverse beam 3 includes a specific end under which a respective longitudinal beam 2 is fixed; these ends are fixed on either side of the midpoint of the longitudinal beam, i.e. 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 downward-extending longitudinal ribs 8. The spreader bar comprises a cable 10, upper pulleys 11, and lower pulleys 12. Each upper pulley 11 is suspended from a rib 8 of the longitudinal beam 2 by a respective shackle 15. A hook 13 is fixed below each lower 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 functionally supported by the upper pulleys 11 and functionally supports the lower pulleys 12.

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

[0032] In the illustrated example, the spreader beam further includes triangulated bracing devices 14. Each brace comprises a hanger 16, here a chain, and a diagonal brace 17, here another chain. The hanger 16 extends substantially vertically downwards from a respective end 2E of the beam 2. A hook 18 is attached to a lower end 19 of the hanger 16. The diagonal brace 17 connects the end 19 of the hanger 16 to a fixing point 21 on the longitudinal beam 2, near its midpoint, here below the nearest transverse beam 3. The hanger and the diagonal brace are not rigid, so as not to impose indeterminate stresses on the part to be lifted. The braces prevent longitudinal displacement of the part to be lifted relative to the spreader beam.

[0033] In the illustrated example, each longitudinal beam comprises 10 high pulleys 11. Of these ten high pulleys, 6 are coupled by pairs of adjacent pulleys 11A, 11B. Figure 3 illustrates such a coupling. The coupling is achieved between two adjacent high pulleys by a spreader 20. Each longitudinal end of the spreader 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, originating from a respective lower pulley, extends from the bottom upwards until it engages in the groove of a first pulley 1IA of the pair. From right to left in [Fig. 3], a second strand 101B of the cable 10, originating from a respective lower pulley, extends from the bottom upwards until it engages in the groove of the second pulley 1IB of the pair. A third strand 101C horizontally connects the first two strands 101A and 101B.

[0035] This forms a high balancing device. Indeed, the spreader 20 maintains the distance 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 (A11A=A11IB). Thus, when the spreader bar is tensioned, and then when the lifting mechanism is activated, the upper pulleys 11A, 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 lower pulleys 11, each equipped with a hook 13. Of these eight lower pulleys, 6 are coupled in pairs. Figure 4 illustrates such a coupling. The coupling is achieved between two adjacent lower 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 lower pulleys 12A, 12B.

[0037] From left to right in [Fig. 4], a first strand 102A of the cable 10, originating from a respective upper pulley, extends 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, originating from a respective upper pulley, extends 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 upper pulley 11, into which it engages. A fourth strand 102D extends the second strand 102B upwards and to the left towards the same intermediate upper pulley 11, into which it engages, in line with the third strand.

[0038] A low balancing device is thus formed. Indeed, the spreader 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 (A12A=A12B). Thus, when the spreader bar is tensioned and then lifted, the upper pulleys 11A, 11IB 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 coupled pulleys prevents longitudinal displacement of the pulleys, thus preventing movement of the workpiece and / or overloading of the workpiece anchors with which the hooks 13 are engaged. This arrangement therefore prevents movement that could be dangerous for a handler or damaging to the workpiece. Furthermore, throughout its handling by a lifting beam according to the invention, the workpiece remains in the position required for its placement, which is thereby facilitated.

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

[0041] It will indeed appear to the person 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

Demands

1. Spreader beam (1) characterized in that it comprises at least one longitudinal beam (2), a set of upper pulleys (11) distributed longitudinally along said beam and suspended from said beam, a cable (10) mounted suspended from the upper pulleys, and a set of lower pulleys (12) mounted rolling on said cable, each lower pulley comprising a grip (13) for anchoring a part to be lifted and at least one upper balancing device and one lower balancing device, a lower balancing device comprising: - a lower pair (12A, 12B) of lower pulleys close to each other; - an intermediate upper pulley (11), disposed between the pulleys of said pair;and, - a spreader (20) for maintaining a spacing between the respective axes (X12) of the pulleys of said lower pair, said cable running from top to bottom to a first pulley (12A) of the lower pair, then being returned from bottom to top by said first pulley, to the intermediate upper pulley and then being returned from top to bottom to the second pulley (12B) of the lower pair, which returns said cable upwards; an upper balancing device comprising: - an upper pair (11A, 1IB) of upper pulleys close to each other; and, - a spreader (20) for maintaining a spacing between the respective axes (X11) of the pulleys of said upper pair, the cable running from bottom to top to a first pulley (11A) of the upper pair and then being returned horizontally to the second pulley (1IB) of the upper pair, and then from top to bottom from said second upper pulley.

2. A lifting beam 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 running from top to bottom to a first of said lower pulleys and then being returned from bottom to top by this first lower pulley, to the first pulley of the upper pair and then being returned horizontally to the second pulley of the upper pair, and then from top to bottom from this second high pulley towards the second low pulley, which returns the cable upwards.

3. Spreader beam according to any 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. Spreader bar according to claim 3; characterized in that the suspension line extends from one end (2E) of the longitudinal beam, the attachment point (21) of the diagonal being near the middle of said longitudinal beam.

5. Spreader bar according to any one of claims 3 and 4, characterized in that the suspension and the diagonal are flexible linear elements, preferably chains or cables.

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