WO1999040021A1

WO1999040021A1 - Equipment for handling oblong objects

Info

Publication number: WO1999040021A1
Application number: PCT/NO1999/000036
Authority: WO
Inventors: Paul Espeland
Original assignee: Norsk Hydro Asa
Priority date: 1998-02-04
Filing date: 1999-02-03
Publication date: 1999-08-12
Also published as: AU2862699A; NO306548B1; NO980481D0; NO980481L

Abstract

Equipment for use in connection with handling oblong objects, in particular billets, bars or ingots of aluminium, comprising a frame (25) with a vertical part (19) and mountings (26, 27) for mounting on a lifting device. The frame also comprises one or more means of contact (21, 22) for placing under one end of the object and one or more means of retention (23, 24) which are above the means of contact at the top of the object. The longitudinal extension of the means of contact is such that the centre of gravity of the object is outside the outer end of the means of contact.

Description

Equipment for handling oblong objects

The present invention concerns equipment for use in connection with handling oblong objects, in particular billets, bars or ingots of aluminium.

In the metal industry, some of the finished metal is cast in billets. Such billets are usually shaped in such a way that the length is much greater than both the thickness and the width, while the width is greater than the thickness. Finished billets are stored in stacks for remelting in, for example, a foundry or rolling in a rolling mill.

When handling such billets today, cranes or wheeled lifting devices such as trucks with lifting equipment are used. The lifting equipment may comprise forks which can be raised and lowered along a lifting tower and can be introduced under the billet to be lifted. However, a disadvantage of this equipment is that the billet lies perpendicular to the direction of travel and will thus require a lot of space during transportation.

When transporting oblong billets using a truck inside a factory hall, it will be expedient to transport the billet so that its longitudinal direction coincides with the direction of travel. This will give the driver a better overview and allow him to exert greater control, while the space required for the truck's path of travel can be kept to a minimum.

It is expedient for furnaces for the remelting of billets to have as small a charging opening as possible, among other things to reduce the emission of heat and gases to the surroundings during charging. These furnaces require that the billets to be remelted are introduced longitudinally.

Wheeled lifting devices in which the lifting equipment comprises a hydraulic gripping device comprising a pair of reciprocating gripping surfaces which are brought into contact with the side surfaces of the billet are known. Such solutions allow the billet to be transported so that its longitudinal direction coincides with the direction of travel.

However, the above solutions are associated with disadvantages in that they represent high acquisition costs and require frequent maintenance/inspection in order to maintain the necessary reliability and safety. This is because, when used as described above, the equipment is subjected to severe physical, thermal and, to some extent, chemical strains and stresses. For example, in connection with charging the furnace for the remelting of aluminium billets, the equipment may be exposed to temperatures up to 1000°C for periods of time. A significant factor of the gripping devices mentioned here is that they depend on the presence of hydraulic pressure, often up to 200 bar, to be able to grip and handle billets safely. If the pressure is removed completely or partially so that the grip of the gripping device on the billet slips, the consequences for life and property may be serious. A standard aluminium billet may weigh approximately 4500 kg and it is thus of great significance for safety that the grip does not slip during transportation in the factory hall or during other handling.

The present invention describes equipment for handling oblong objects such as billets, ingots or bars with which the above disadvantages can be avoided. The equipment is simple and cheap to produce and is subject to very little wear during use. The latter feature is achieved in particular because the equipment does not comprise parts which move when a grip on the billet is to be established.

The present invention is to be described in the following in further detail using examples and figures, where:

Fig. 1 shows a wheeled lifting device with equipment for charging a furnace, seen from the side, Fig. 2 (a-c) shows a first embodiment of equipment for use in connection with handling oblong billets, where 2a shows the equipment from the side, 2b shows the equipment from above and 2c shows a detail of the equipment seen from the side,

Fig. 3 shows, seen from the side, a second embodiment of a means of retention of the equipment shown in Fig. 2,

Fig. 4 shows, seen from the side, a third embodiment of equipment for use in connection with handling oblong blocks,

Fig. 5 (a-b) shows equipment for lifting profiles in bundles for remelting, where a shows the equipment from the side and b shows the equipment from above,

Fig. 6 (a-c) shows another embodiment of equipment for lifting profiles in bundles, where a shows the equipment from the side, b shows the equipment from above and c shows the equipment from the front,

Fig. 7 (a-c) shows equipment for lifting ingots for remelting, where a and b show the equipment from the side for lifting ingots of a small and large diameter respectively and c shows the equipment from the front.

As figure 1 shows, a wheeled lifting device 1 is equipped with equipment 2 for charging an aluminium billet 4 in a melting furnace 3. The furnace comprises conventional means for heating, run-off and extraction (not shown). Moreover, the furnace has an opening 5 through which the metal billets are charged. In the furnace there is a bath of molten metal 6 and the furnace's opening is designed so that emissions of gases to the hall atmosphere are as low as possible and that the charging can take place in a simple, safe manner. As the figure shows, during charging the equipment 2 extends through the opening and into the heated zone of the furnace. The billets are charged into an empty furnace and can be placed in the furnace in a controlled manner.

The wheeled lifting device 1 can, in conventional manner, comprise lifting arms or a lifting tower equipped with standard mountings for equipment (not shown) and can move lifting equipment vertically in a known manner. The lifting equipment can also expediently be given limited rotation about a horizontal transverse axis (tilting) using the lifting device. Such lifting devices and lifting movements are known to experts and will not be described further here.

Figures 2a, 2b and 2c show in more detail a first embodiment of equipment for handling oblong billets 20. The equipment shown in this example comprises a frame 25 with a vertical part 19, two lower means of contact 21 , 22 and two upper means of retention 23, 24. The means of retention23, 24 can be equipped with one or more beads or pins 29 which come into contact with the upper surface of the billet. The frame 25 is equipped with standard mountings 26, 27 for mounting on a wheeled lifting device.

The mode of operation of the equipment requires that the billets have a centre of gravity which is outside the outer ends 28 of the lower means of contact. Under the impact of the centre of gravity, the billet will tend to tilt about the outer ends of the means of contact and will thus be brought into contact with the means of retention 23, 24. Forces arise here the size of which will depend on the weight of the billet and the location of its centre of gravity.

The beads or pins 29 of the means of retention can expediently have a design which contributes to the forces which are to be transferred between the means of retention 23, 24 and the billet 20 being transferred via a relatively limited area. This means that the contact pressure between the pins 29 and the billet 20 can be made sufficiently great to ensure that a safe grip is achieved. If this area is made very small, for example by designing the beads or pins 29 with a pointed end, the result may be that they produce local deformation of the material and are pressed into it. Figures 2b and 2c show that the means of retention 23 can be designed from plate-shaped elements 30, 31 which are linked by means of a plate 33. The plate-shaped elements 30, 31 are, in this embodiment, equipped with beads or pins 29 at their lower parts. The plate 33 may extend below the elements 30, 31 and be designed with beads at its lower part (not shown).

Fig. 3 shows, seen from the side, a second embodiment of a means of retention 23'. The means of retention can, as in the previous example, consist of a plate construction (not shown) to which a pin 29' is fixed. The pin can be fixed to the plate construction by means of welding and can, moreover, consist of a cylindrical body which has a conical end 34' at its contact end 35'. The lower edge 18' of the means of retention 23' can expediently slope downwards slightly towards its outer end, preferably so that it forms an angle of 9 to the horizontal plane.

Figure 4 shows a side view of a third embodiment of equipment for use in connection with handling oblong billets 20". The billet 20" to be lifted in this example is here supported on a base using distance blocks or sills 36", 37". As in the previous examples, the equipment comprises a frame 25" with a vertical part 19", means of contact 22" and means of retention 23". The means of retention 23" are provided with a pin 29" as in the previous example. The means of contact and retention can comprise pairs of means equivalent to those shown in the previous examples or they can comprise one relatively wide means of contact and one or more means of retention (not shown).

The equipment described in the examples can, moreover, comprise securing devices to support the billet laterally (not shown). Such securing devices can comprise means of contact or retention which are fixed to the frame and mounted on each side of the billet and will prevent the billet rotating about its vertical axis.

Moreover, the vertical part 19, 19" of the frame 25, 25" can be designed in such a way that it can be extended/shortened in a simple manner, which means that the equipment can easily be adapted to billets of different thicknesses. The vertical part can expediently comprise a telescopic link of a known type comprising two mutually telescopic elements which can be locked to one another (not shown). Such links can comprise telescopic tubes. Alternatively, the means of retention can be fitted with slides which are fixed to the vertical part of the frame by means of a vertical rail/slide link in which the position of the slide can be fixed along the rail (not shown).

Figure 5a shows a side view of equipment for handling bundles 120 of material to be remelted. Like the solutions described above, this example comprises means of contact 122 and means of retention 123 which mainly travel horizontally. In order to achieve a better grip, both the means of contact and the means of retention can be designed with teeth in a zigzag pattern 128, 129 in a plate-shaped material; see figure 5b, which shows the equipment from above. The means of contact and retention can be linked by side frames 124, 125.

Figure 6a-c shows alternative equipment for handling bundles 120' of material to be remelted. As in the previous embodiment, the equipment comprises means of contact 122' and means of retention 123' which are linked by side frames 124', 125'. Figure 6a shows the equipment from the side while figure 6b shows the equipment from above. The means of contact, means of retention and side frames can expediently be designed so that together they form a cylindrical or trough-shaped body; see figure 6c, which shows this equipment from the front.

Figure 7a-c shows equipment which is designed to lift ingots 220, 220', in particular reject ingots which are to be remelted. Such ingots normally have a circular cross-section and are of varying diameter. Consequently, the lifting equipment can have a shape which is adapted to them. The equipment comprises means of contact 222 and means of retention 223, 223'. In addition, side supports in the form of one or more diagonal stays 224 can be fitted. Figure 7a shows the equipment from the side, lifting ingots 220 with a small diameter, while figure 7b shows the equipment from the side, lifting ingots 220' with a large diameter. Figure 7c shows the lifting equipment from the front, where means of retention 223, 223' are mounted at various vertical 7

levels to handle ingots with a small or large diameter. The means of retention 223, 223' can expediently comprise transverse beams which have a lower surface which exerts great friction against the ingots. This can, for example, be achieved by the surface being roughened or having beads or small spikes fitted.

Claims

1. Equipment for use in connection with handling oblong objects such as billets, bars or ingots, in particular of aluminium, comprising a frame (25) with a vertical part (19) and mountings (26, 27) for mounting on a lifting device, characterised in that the frame also comprises one or more means of contact (21, 22) for placing under one end of the object and one or more means of retention (23, 24) which are above the means of contact and at the top of the object, and that the longitudinal extension of the means of contact is such that the centre of gravity of the object during handling is outside the outer end of the means of contact (21, 22).

2. Equipment in accordance with claim 1 , characterised in that the means of retention (23, 24) comprise at least one bead or pin (29).

3. Equipment in accordance with claim 2, characterised in that the bead or pin comprises a cylindrical body 29' with a conical end 34' at its contact end 35'.

4. Equipment in accordance with claim 1 , characterised in that the means of retention (23') comprise a lower edge (18') which slopes downwards slightly towards its outer end, preferably so that it forms an angle of 9┬░ to the horizontal plane.

5. Equipment in accordance with claim 1 , characterised in that the means of retention (123) and means of contact (122) comprise teeth in a zigzag pattern designed in a plate material (129, 128).

6. Equipment in accordance with claim 1 , characterised in that the vertical part of the frame (19) can be extended/shortened using a telescopic link.

7. Equipment in accordance with claim 1 , characterised in that the frame comprises securing devices (224) or side frames (124', 125') to support the object laterally.

8. Equipment in accordance with claim 7, characterised in that the means of contact (122'), means of retention (123') and side frames (124', 125') are linked together and preferably constitute a cylindrical body.

9. Equipment in accordance with claim 1 , characterised in that the means of retention (223, 223') can be mounted at different vertical levels.

10. Equipment in accordance with claim 9, characterised in that the means of retention (223, 223') can comprise traverse beams, the lower surfaces of which are formed in such a way that they exert great friction against the objects which are to be handled.