WO1998043888A1

WO1998043888A1 - Pallet and method for handling a coil, and hoisting element for use therein

Info

Publication number: WO1998043888A1
Application number: PCT/NL1998/000190
Authority: WO
Inventors: Johannus Jozefus Hubertus Thomas; Martin Esselbrugge; Cornelis Stinis; Aran Van Belkom
Original assignee: Lankhorst Recycling B.V.; Laura Metaal Eygelshoven B.V.; Stinis Beheer B.V.
Priority date: 1997-04-03
Filing date: 1998-04-03
Publication date: 1998-10-08
Also published as: AU6750598A; NL1005710C2

Abstract

A pallet for storing, shipping and transporting coiled products of great weight, having a support part (4; 104, 136) from a first material and a support structure (5; 105) from a second material, which is harder and stronger than the first material. The support structure (5; 105) has a coupling part (6; 106) for coupling to a coupling part (7; 107) of a hoisting element (3; 103). Such pallet can be hoisted by a local coupling portion of the pallet with a very heavy coil in a position in which the center line of the coil is vertical without the pallet and the coil resting thereon being unduly deformed or collapsing. The coil is supported on its lateral side without the edges of the coil being damaged. Further described are a method for using such pallets and a hoisting element for cooperating with a particular embodiment of such pallet.

Description

Title: Pallet and method for handling a coil, and hoisting element for use therein.

The invention relates to a pallet according to the preamble of claim 1 and to a method according to the preamble of claim 16.

Such pallet and such method are known from European patent specification 0 242 454. This known pallet is particularly suitable for storing, shipping and transporting rolls or spools, also referred to as coils, up to a weight ^"of about 15 tons. Moreover, for heavier coils, an adaptability to variations in coil diameter over a large diameter range is required.

Further, for hoisting such pallet and a coil supported thereby, it is necessary to provide slings around the whole. After the whole has been positioned, these slings must also be detached again. This requires time and additional manpower and has therefore a cost-increasing effect.

Up to the present, heavier coils, such as coils of steel for the automobile industry, have been shipped and transported on wooden pallets in a position in which the center line about which the coil is coiled is horizontally oriented. This entails a substantial risk of damage to the outer windings and the edges of the plate material. Moreover, because the lying coils can roll easily, transport over the sea requires a highly stable and accurate stowing of the load. Cases are known where an inadequate stowing of such load resulted in the capsizing and sinking of ships.

The object of the invention is to provide a solution to the problem of quickly shipping very heavy coils of material, while limiting the risk of damage and limiting the sensitivity of a load of such coils to inadequacies in the stowing of the load.

In accordance with the present invention, this object is attained by designing a pallet as initially referred to according to the characterizing portion of claim 1. Moreover, the invention provides that a method for hoisting as initially referred to is carried out according to the characterizing portion of claim 16.

Since the pallet is provided with a support structure from a second material, which can be subjected to a heavier mechanical load than the first material, and since the support structure comprises a coupling part for coupling to a coupling part of a hoisting element, a pallet with a very heavy coil in a position in which the center line of the coil is directed vertically can be hoisted by means of a hoisting element having a coupling part engaging a local coupling portion of the pallet, without the pallet and the coil resting thereon being unduly deformed or collapsing. In fact, more coupling parts of the hoisting element may also engage more coupling parts of the pallet. The softer material of the support part or the support parts provides that the coil is supported on its lateral side without any particular danger of damage to the edges of the coiled up material.

In accordance with a particular elaboration of the invention, the pallet comprises a centrally located coupling part which is accessible to a hoisting element through the vertically directed core hole of a coil sitting on the pallet. In this manner, a coil can be coupled to a hoisting element with a single coupling.

To cause the coil to be automatically suspended in a stable position during hoisting, the invention further provides a special hoisting element according to claim 15. The centering surface at a distance in the hoisting direction from the coupling portion of the hoisting element centers the coil relative to the pulling element of the hoisting element, which pulling element, due to the weight of the hoisted load, extends substantially vertically during hoisting. Thus, the coil in hoisted condition is automatically stabilized in a substantially vertical position. The centering surface further limits the risk of damage to the inner windings and the inner top edge of the coil. Particular elaborations of the invention are laid down in the dependent claims .

Hereinafter, further objects, embodiments, effects and advantages of the invention are specified on the basis of some exemplary embodiments, with reference to the accompanying drawings, wherein:

Fig. 1 is a bottom view of a pallet according to the invention and a coil positioned thereon;

Fig. 2 is sectional side view taken on the line II-II in Fig. 1 ;

Figs. 3-5 are schematic top plan views of parts of a pallet in combination with coils having different diameters;

Fig. 6 is a top plan view of a main flange of a support structure of a pallet; Fig. 7 is a combination of side views in central section of halves of support structures according to two different embodiments;

Fig. 8 is a top plan view of a coupling part of one of the support structures according to Fig. 7; Fig. 9 is a sectional view taken on the line IX-IX in Fig. 8;

Fig. 10 is a perspective view of a support part of a pallet according to Figs. 3-5;

Fig. 11 is a detailed top plan view of a support part of a pallet according to a further exemplary embodiment;

Fig. 12 is a front view of the pallet according to Fig. 11;

Fig. 13 is a side view of the pallet according to Fig. 11; Fig. 14 is a cutaway top plan view of a hoisting element according to the invention;

Fig. 15 is a sectional view taken on the line XV-XV in Fig . 14 ; and

Figs. 16-18 are top plan views, in two positions, of another exemplary embodiment of a pallet according to the invention, in side elevation and partly in cross section, and the associated support structure.

Figs. 1 and 2 show a pallet 1 according to the invention in combination with a coil 2 supported by that pallet 1 and a hoisting element 3 according to the invention. The pallet 1 is suitable for storing, shipping and transporting coiled products of great weight, such as coils of automobile steel or large coils of paper and wood veneer. Coils of wire or cable material can also be stored, shipped and transported on such pallet 1, possibly in a slightly modified version.

The pallet 1 is composed of support parts 4 made from a yielding material (in this case waste polyethene plastic, but other yielding materials, such as wood and rubber, may also be used) and a steel support structure 5. For the support structure 5, too, other materials can in principle be used, such as aluminum or composite materials . The material of the support structure 5 is harder and stronger than the material of the support parts 4. The support structure 5 comprises a coupling part 6 for coupling to a coupling part 7 of a hoisting element such as hoisting element 3.

Unlike pallets that are hoisted in a sling, in the pallet 1 according to the invention the hoisting force is introduced very locally at the location of the interlocking coupling parts 6, 7 of the pallet 1 and the hoisting element 3. Because the pallet 1 comprises a support structure 5 made from a material which can be subjected to a heavier mechanical load than the material of the support parts, a pallet 1 with a very heavy coil 2 (a coil of steel for the automobile industry typically weighs about 30 tons) can be hoisted in a position in which the center line 8 is directed vertically by means of a very locally engaging coupling, without the pallet 1 and the coil 2 resting thereon being unduly deformed or collapsing. The yielding material of the support parts 4 on which the coil 2 rests provides that the coil 2 is supported on its lateral side without a particular risk of the edges of the coil 2 being damaged. Further, because the orientation of the coil 2 with the center line 8 is directed vertically, the chance of damage to the outer winding is limited. As this involves the support parts 4 projecting outside the coil 2, it is effected that during the loading of a ship, the thrusts between adjacent coils are transmitted via the support parts 4, which further limits the danger of damage to the coils.

Because during hoisting, a coupling part of a hoisting element is coupled to a coupling part of the pallet, and the assembly is hoisted while suspending from the hoisting element by means of the coupled coupling parts, the necessity of providing slings ceases and the pallet can be picked up and released very quickly, as a result of which loading and unloading requires less manpower and can be performed more quickly.

The pallet 1 is attached to a coil 2 after the material of the coil has come from a roller and the coil has been formed in a lying position. For attaching the pallet 1, it is placed against the coil 2 and tensioning belts 9, extending around it vertically, are passed along the outer circumference, through openings in the support parts 4, through the core hole 10 of the coil 2 and along the side face of the coil 2 remote from the pallet 1, and tensioned, whereafter portions of the tensioning belts 9 are welded relative to each other to form a loop. Further, a horizontal tensioning belt 11 is provided around the pallet 1, which pulls the support parts 4 inwards in radial direction, until raised edges 12 thereof abut at least partly against portions of the outer circumference of the coil 2. The coil is now ready for being tilted into the position shown in Fig. 2, with a vertically directed center line 8. For this purpose, a hoisting element as shown in Fig. 2 can be used, possibly with adjustments so as to be able to resist the moment to be exerted during tilting, which moment is greater than in the case of hoisting during loading or unloading, and to introduce that moment without damaging the coil .

In principle, it may be provided that more than one coupling of the hoisting element engage more than one coupling part of the pallet. To this end, the pallet can for instance comprise three or four coupling parts distributed over the outer circumference. For an efficient construction of the pallet and the hoisting element, and for limiting the loss of space by parts of the pallet projecting outside the coil, an embodiment of the pallet as shown is preferred, with the coupling part 6, at least in operational condition and viewed from the top, being centrally located, enabling the coil to be hoisted with a single coupling within the contour of that coil. The coupling part 6 of the pallet 1, shown in more detail in Figs. 7 (right half), 8 and 9, is constructed with an opening 13 and a chamber 14 below that opening 13 for receiving a coupling pawl 15 of a hoisting element 3. With such coupling, a coupling between the coupling parts, which during the coupling operation are concealed from the crane driver in the coil to be hoisted, can be effected in a reliable manner. For the coupling operation, difficultly controllable lateral movements of the hoisting element are not necessary. The coupling parts shown in Figs. 7 (right half) , 8 and 9 form part of a twistlock system, known per se and used in practice for coupling sea containers and the like to a hoisting element .

The coupling part 6 comprises reinforcement flanges 16 which, in the assembled condition shown in Fig. 7, are secured by welding to a main flange 17 of the support structure. The support structure 5 further comprises a bowl- shaped part 18 providing a more uniform transmission of forces exerted on the coupling part 6 to radially outer portions of the support structure 6. In the example of Fig. 6, the main flange 17 is composed of two identical disk- shaped halves which are profiled so as to be cross-shaped and locally welded together. By the profiling of the disks of the main flange 17, radially directed box-shaped support portions 19 are formed therein, which have a great resisting moment to bending . The hoisting element 3 is further provided with a drawbar 20, projecting in operational condition in a hoisting direction from the coupling part 7, for taking up the tensile loads 20 which occur during hoisting, and with radially outwardly facing centering surfaces 21, 22, which in the hoisting direction (arrow 23) are remote from the coupling part 7 of the hoisting element 3.

The centering surfaces 21, 22 center the coil 2 relative to the drawbar 20 of the hoisting element 3, which extends substantially vertically due to the hoisting force. In this manner, the coil 2 is stabilized in a substantially vertical position during hoisting. Since the drawbar 20 of the hoisting element 3 is tightened during hoisting, it is also possible to use a cable, chain or another flexible pulling element instead of a bar, without undoing the stabilizing action of the centering surfaces 21, 22 projecting radially from the pulling element.

The centering surfaces further limit the risk of damage to the inner windings and the inner top edge of the coil 2. With the hoisting element shown, a particularly effective protection of the coil 2 is obtained in that the centering surfaces 21, 22 are designed as circumferential surfaces of centering plugs 24, 25 made from yielding material. Of course, instead of two centering, surfaces, one single centering surface or more than two centering surfaces may be used as well. By providing the hoisting element with a number of centering plugs that can be moved back and forth in hoisting direction and that have in each case a larger diameter than a subjacent plug, an automatic adaptation to the diameter of the core hole of the coil 2 to be hoisted can further be effected. Since the centering surfaces taper conically in the direction of the coupling part 7, the hoisting element is centered relative to the coil 2 when it is being inserted into the core hole, which simplifies the insertion. Picking up the assembly of a coil 2 and a pallet 1 by inserting the hoisting element 3 into a core hole 10 around the center line 8 of the coil 2 and coupling it in or under the core hole 10 to the coupling part 6 of the pallet 1, can be effected particularly quickly, because the orientation of the hoisting element in the horizontal plane does not play a part or, due to the slight moment of inertia of the radially compact hoisting element 3 about the vertical axis, can very quickly be adapted to the orientation of the coupling part 6 of the pallet 1. Shown in the left half of Fig. 7 is a coupling part 106 which is especially adapted for cooperation with a hoisting element 103 of which a bottom end is shown in Figs. 14 and 15. The coupling part 106 has an opening 113 and, located therebehind, a chamber 114 for receiving a pawl 115 of a coupling part 107 of a hoisting element 103. This opening 113 has a circular circumference, which offers the advantage that the coupling part 107 of the hoisting element 103 can be brought into engagement with the coupling part 106 regardless of the mutual orientation of the coupling parts 106, 107 around the vertical axis.

To enable cooperation with such coupling part 106 having a circular opening 113, the coupling part 107 of the hoisting element 103 is provided with hoisting pawls 115 which are movable with a radial movement component between a first, projecting position 115 for engaging the coupling part 106 of a pallet and a second, withdrawn position 115' for coupling to and releasing the coupling part 106 of a pallet.

More in particular, the coupling part 107, shown by way of example, comprises a head 126 fitting with a slight play in the opening 113 of the coupling part 106 of the pallet to be hoisted. The pawls 115 project in radial direction from operating shafts 127 parallel to the hoisting direction, which operating shafts are bearing-mounted in the coupling part 107 for rotation about their center lines. At their ends remote from the pawls 115, the operating shafts 127 are provided with gear wheels 128 which are in mesh with a distribution gear wheel 129 mounted on the end of the drawbar 120. The drawbar 120 may for instance be rotatable in the same manner as the drawbar 20 of the hoisting element shown in Fig. 1, in which the principle of twistlock couplings, known per se, is used.

By rotating the drawbar 120 relative to the coupling part 107, the distribution gear wheel 129 is rotated, causing the gear wheels 128 and the operating shafts 127 to be moved along and the pawls 115 to be swivelled from the withdrawn position 115' into the projecting position 115 or vice versa. The coupling part 107 further comprises a locking which unlocks the coupling pawls 115 only in response to a state of a sensor 130 indicating that the coupling part 107 of the hoisting element 103 abuts against the coupling part of a pallet without exerting hoisting force. In the coupling part shown in Figs. 14 and 15, that sensor is designed as a pin 130 which projects downwards from the head 126 of the coupling part 107 and which is depressible against a force exerted by a spring 131. In the projecting position, a part of the pin 130 engages one of the recesses 132, 133 in a locking edge 134 which can be rotated along with one of the gear wheels 128. In this condition, the coupling part 107 is blocked. When the pin 130 is depressed, a flat part of the pin 130 is located opposite the locking edge 134 and the gear wheels 128 can rotate. In this condition, which in operation occurs only if the head 126 of the coupling part 107 abuts against a coupling part of a pallet, which means that engagement is possible, but no hoisting force is exerted, the coupling part 107 is unlocked. Thus, a coil cannot fall down through the accidental actuation of an operating member for unlocking, while the coil is being hoisted. Also, the pawls 115 cannot accidentally be brought into the projection position without this resulting in the coupling of a pallet.

Particularly in the case of larger coils of steel plate, the diameter may differ considerably from coil to coil. To be able to take up such variations in diameter, the pallets according to the embodiments shown comprise two support parts which are mounted so as to be displaceable between positions with different mutual intermediate distances. The adjustability of the diameter of the pallets is explained with reference to the exemplary embodiment shown in Figs. 3, 4, 5 and 10. If a coil of a smallest possible diameter (in this example 1600 mm) is placed on a pallet 101 (see Fig. 3), the support parts 104 (one of which is in each case shown in Figs. 3, 4, 5 and 10) are in positions in which they substantially abut against each other. According as larger coils 102 are placed, the distance between the support parts 104 is larger (Figs. 4 and 5) . As Figs. 1 and 2 demonstrate, the support parts 104 are pulled towards each other by means of tensioning belts extending in grooves 135 in raised edges 112 of the support parts 104.

To ensure that the inner windings of the coil are also properly supported if a coil having a small core hole 10 is placed on the pallet 101, the pallet 1 comprises a third central support part 136, which, in operational condition and in top plan view, is centrally located between the other, more peripheral support parts 104. The central support part 136 has in each case two radially projecting tongues 137 which overlap the other, more peripheral support parts 104 in radial direction. In this manner, also of the inner windings at least two circular sections are in each case supported by yielding material of the support parts, and an intermediate number of windings is further prevented from not being supported.

In order to center the coils 102 relative to the support structure 105 supporting the coupling part 207, the pallet 101 is provided with a centering 138 which projects centrally upwards from the support structure 105.

Because the central support part 136 covers a radially outer portion of the centering, the coil 102 is prevented from being damaged by contacting the centering.

The support parts 104 are each provided with two circle sector parts 139 for supporting different circle sectors of a coil 102, and a flexible pivot portion 140 which pivotally interconnects the circle sector parts 139 adjacent the outside contour of the pallet 101.- When the support parts 104 are pulled around a small coil 102 by the tensioning belt, as shown in Fig. 3, the circle sector parts 139 swivel towards each other and the raised edges 112, which in unloaded condition extend according to parabolic lines, adjust themselves to the outer circumference of the coil 102. When the support parts 104 are pulled around a coil of average size, they approximately maintain their original shape (Fig. 4) . When the support parts 104 are pulled around a large coil (Fig. 5) , they bend away from each other and the raised edges 112 adjust themselves to the outer circumference of the coil 102. Such embodiment of the support parts 104 offers the advantage that with a particular number of support parts, substantially the same adaptability to different coil diameters can nevertheless be obtained as with a larger number of loose, non- flexible or non-pivotable support parts. Some further aspects of the support parts will be specified on the basis of the exemplary embodiment shown in Figs. 11-13 and with reference to Figs. 1 and 2.

The support parts 4 and the support structure 5 comprise cooperating projections 41 and recesses 42 bounding the movability of the support parts 4 and the support structure 5 relative to each other. In this manner, the coherence of the pallet is also maintained if it is not attached to a coil. This simplifies the logistic handling of the pallets 1 and in particular the return transport, which is readily possible in stacked condition in a container. Because the recesses 42 are oval, a great adaptability to different coils and possible unroundness thereof is obtained. Further, this prevents the support parts 4 from blocking when the tensioning belt 11 is tightened in intermediate positions prior to a proper abutment of the raised edge 12 against the relevant coil 2.

The support parts 4 each have a slot 43 which, in assembled condition, receives the main flange 17 of the support structure 5. As a result, the support parts 4 extend both on the top side and on the bottom side of the support structure 5. This offers the advantage that not only a coil sitting on the support structure is protected from damage, but also any subjacent coil. In practice, this enables stacking of automobile steel up to a height of four coils . Figs. 16 and 17 schematically show, in top plan view and partly in section, an example of an alternative embodiment of a pallet according to the invention in a first position (Fig. 16) for coils having a relatively large diameter and a second position (Fig. 17) for coils having a smaller diameter. Fig. 18 schematically shows a support structure 180 suitable for use in a pallet according to Figs. 16 and 17.

The support structure has again a central portion 181 for accommodating a coupling part of a hoisting element. The central portion has two radial arms 182, 183 with, at the ends thereof, vertical pins 184, 185 extending into slots 186, 187 in the support parts 188, 189. The support structure is arranged such that on either side thereof, there is sufficient space for forming receiving recesses in which the fingers of a forklift truck, the legs of a C-hook, and the like, can be received. The receiving recesses are schematically indicated by arrows 190, 191. It is also possible to use the receiving recesses for fitting slings. In this manner, the pallet is universally employable and can also be handled in locations where no special hoisting apparatus is available. The pallet of Figs. 16-18 has a support structure 180 with, in this example, a cylindrical central portion 181 and a shoulder 192 extending around the cylindrical portion, which shoulder, in operation, supports a number of the inner windings of a coil. The more outwardly located windings are supported by the radial arms 182, 183. The arms may have a shape other than shown in the Figure . The arms may for instance have a wide foot adjacent the central portion and then narrow down towards the ends . For the sake of completeness, it is observed that in this embodiment, too, the coils to be transported do not rest directly on the support structure, but on a yielding material, such as plastic .

It is observed that after the foregoing, various modifications will readily occur to a skilled person. Both in the shape of a support structure and in the shape of the support parts of yielding material, many modifications are conceivable. The hoisting element, too, can be constructed in various manners. For instance, a single rotatable coupling part may be used, but also coupling parts having two slidable and/or rotatable pawls or more than two of such pawls are applicable, together with a correspondingly shaped coupling part of the support structure.

Such modifications are understood to fall within the framework of the appended claims.

Claims

1. A pallet for storing, shipping and transporting coiled products of great weight, comprising at least one support part (4; 104, 136) from a first material, characterized by a support structure (5; 105) from a second material, which is harder and has a greater strength than said first material, the support structure (5; 105) comprising a coupling part (.6 ; 106) for coupling to a coupling part (7; 107) of a hoisting element (3; 103) .

2. A pallet according to claim 1, wherein said coupling part (6; 106), in operational condition and viewed from the top, is centrally located.

3. A pallet according to claim 1 or 2 , wherein said coupling part (6; 106) comprises an opening (13; 113) and a chamber (14; 114) under said opening (13; 113) for receiving a coupling pawl (15; 115) of a hoisting element (3; 103) .

4. A pallet according to claims 2 and 3, wherein said opening (113) has a substantially circular circumference.

5. A pallet according to any one of the preceding claims, further comprising at least two of said support parts (4; 104) which are mounted so as to be displaceable between positions with different intermediate distances relative to each other.

6. A pallet according to claim 5, wherein the support parts (4; 104) and the support structure (5; 105) comprise cooperating projections (41) and recesses (42) bounding the movability of the support parts (4; 104) and the support structure (5; 105) relative to each other.

7. A pallet according to claim 5 or 6 , further comprising at least a third one of said support parts (136) , which, in operational condition and viewed from the top, is centrally located between said at least two displaceable, more peripheral support parts (4; 104), the central support part (136) having at least one radial projection (137) which overlaps said more peripheral support parts (4; 104) in radial direction.

8. A pallet according to any one of the preceding claims, further comprising a centering (138) , projecting centrally upwards from the support structure (5; 105) for centering the support structure (5; 105) relative to a coil (102) .

9. A pallet according to claims 7 and 8, wherein the central support part (136) at least partially covers or forms at least a radially outer portion of said centering.

10. A pallet according to any one of the preceding claims, wherein the at least one support part (4; 104) is designed with at least two circle sector parts (139) for supporting different circle sectors of a coil (102) and a pivot portion (140) which pivotally interconnects said circle sector parts (139) adjacent the outer contour of the pallet (101) .

11. A pallet according to any one of the preceding claims, wherein the at least one support part (4; 104) is designed with at least two circle sector parts (139) for supporting different circle sectors of a coil (102) and a flexible portion (140) which flexibly interconnects said circle sector parts (139) adjacent the outer contour of the pallet (101) .

12. A pallet according to any one of the preceding claims, wherein the at least one support part (4; 104) extends at the top side and the bottom side of the support structure (5; 105) .

13. A pallet according to any one of the preceding claims, characterized in that the support structure (180) is of such design that on either side thereof there is space for receiving recesses (190, 191) for receiving the fingers of a fork-shaped hoisting element.

14. A pallet according to any one of the preceding claims, characterized in that the support structure (180) comprises a central coupling part (181) and a shoulder (192) extending around the coupling part, which shoulder, in operation, is located under the innermost part of a product, the support structure further comprising two diametrically opposed, outwardly extending arms.

15. A pallet according to claim 14, characterized in that the at least one support part comprises receiving recesses, located on either side of the arms, for elongated elements of the lifting and/or transport means.

16. A method for hoisting an assembly comprising a coiled product having a center line (8) around which the product is coiled, said product standing on a pallet (1; 101) with said center line (8) oriented vertically, characterized in that a coupling part (7; 107) of a hoisting element (3; 103) is coupled to a coupling part (6; 106) of said pallet (1; 101) and the assembly is hoisted while suspending from the hoisting element (3; 103) by means of said coupled coupling parts (6, 7; 106, 107) .

17. A method according to claim 16, wherein the assembly is picked up by inserting the hoisting element (3; 103) into a core hole (10) around which the product is coiled and coupling it to the coupling part (6; 106) of said pallet (1; 101) in or under said core hole (10) .

18. A hoisting element for hoisting an assembly comprising a pallet (1; 101) and, resting thereon, a coiled product

(2; 102) of great weight, comprising a coupling part (7; 107) for coupling to a coupling part (6; 106) of the pallet (1; 101), a pulling element (20; 120) for taking up pulling forces, which pulling element in operational condition projects from the coupling part (7; 107) in a hoisting direction (23) , and at least one radially outwardly facing centering surface (21, 22) which in the hoisting direction (23) is located at a distance from said coupling part (7; 107) of the hoisting element (3; 103).

19. A hoisting element according to claim 18, wherein the centering surface (21, 22) tapers conically in the direction of the coupling part (7; 107) .

20. A hoisting element according to claim 18 or 19, wherein the coupling part (107) has one or more hoisting pawls (115) which are movable with a radial movement component between a first, projecting position (115) for engaging the coupling part of a pallet, and a second, withdrawn position (115') for coupling to and releasing the coupling part (106) of a pallet.

21. A hoisting element according to any one of claims 18-20, wherein the coupling part (107) comprises at least one coupling pawl (115) which is displaceable between a projecting and a withdrawn position, and a locking (130) which unlocks said coupling pawl (115) in response to a condition in which the coupling part (107) of the hoisting element (103) abuts against the coupling part (106) of a pallet without exerting a hoisting force.