Per
Bisg�rd
Per
Bisg�rd
| 1. | Lifting apparatus for use in the stacking of empty pallets on a base or floor, where the first pallet in a stack is placed on the floor, e.g. with a pallet truck, or for the destacking of pallets placed in a stack on a base or floor, where the apparatus comprises a base part arranged to rest on a base or floor, and carriers arranged to support a pallet, where the carriers are connected to and suspended in a substantially vertically displaceable manner in relation to the base part, and where the carriers are further suspended so that they can assume one or more first positions in which they can support a pallet, and one or more other positions in which they can not support a pallet, wherein the change in position of the carriers can be effected in forced dependence of apron guides during the vertical raising and lowering of the carriers, characterized in that on the base part and vertically displaceable in relation to the base part there is a frame part which supports the carriers, where the carriers can be moved sideways in relation to the frame part, and where the movement of the carriers in relation to the frame parts is determined by the apron guides which can force the carriers into certain positions in relation to the frame part during the vertical movement of the frame part, and that each apron guide is disposed on the side of a plate part which has two different apron guides on mutually opposite sides, of the plate part, and in that the plate part is mounted in the apparatus in such a manner that it can be turned 180° so that an apron guide by choice can be brought into engagement with a carrier in the apparatus. |
| 2. | Lifting apparatus according to claim 1, characterized in that the apparatus has two frame parts arranged in parallel, each of which supports two carriers. |
| 3. | Lifting apparatus according to claim 1 and comprising at least one pressure means cylinder, characterized in that the base part is horseshoeshaped with two oppositely facing, straight and parallel side parts, where each of the side parts is provided with a pressure cylinder which can displace a yoke in the vertical direction, where each end of said yoke directly or indirectly supports the frame part and is controlled by vertical guides. |
STATE OF THE ART
The invention relates to a lifting apparatus for use in the stacking of empty pallets on a base or floor, where the first pallet in a stack is placed on the floor, e.g. with a pallet truck, or for the destacking of pallets placed in a stack on a base or floor. The apparatus comprises a base part arranged to rest on a floor, and carriers arranged to support a pallet, mainly along the side edges of its upper boards. The carriers are connected to and housed in a vertically displaceable manner in relation to the base part, and the carriers are further housed so that they can assume one or more first positions in which they can support a pallet, and one or more other positions in which they can support a pallet. The change in the position of the carriers can be effected in forced dependence of apron guides during the vertical raising and lowering of the carriers.
Such an apparatus is known from DE published application no. 1,938,538. This apparatus can function as a stacker and as a destacker. However, this requires two different configurations for the apron guides which control the carriers. Here, each of the carriers is built-in and can be displaced in a post where the apron guide constitutes a side part of the post. Therefore, in addition to the changing of the guide, changes in the pattern of movement also require the dismantling of the carrier.
Other pallet lifting apparatus with quite complicated moving mechanisms is also known from other sources, in that these have several means of displacement for movement in
different directions and are controlled by P C control or other complicated electronics.
EXPLANATION OF THE INVENTION
The innovative aspect of the lifting apparatus according to the invention is that on the base part there is provided a vertically-displaceable frame part which supports the carriers, where the carriers can be moved sideways in relation to the frame part. The movement of the carriers in relation to the frame parts is determined by the apron guides, which can force the carriers into certain positions in relation to the frame part during the vertical movement of the frame part. Moreover, each apron guide is arranged on the side of a plate part which has two different apron guides, one on each side of the plate part, and the plate part is mounted in the apparatus in such a manner that the plate part can be turned 180°, so that a given apron guide can be brought into engagement with a carrier in the apparatus.
The number of displacement elements can be reduced to a maximum of two, one on each side of the pallet stack. By configuring apron guides on opposite sides of a plate part, two different possibilities are provided of guiding the carriers. Changeover between the two different possibilities can be carried out in a simple manner by turning the plate part 180° around an axis through its main plane. Normally, there will be two plate parts for each frame part in order to provide sufficiently reliable control of the carriers.
A preferred embodiment is disclosed in claim 2, where the apparatus has two frame parts arranged in parallel, each of which supports two carriers.
Another preferred embodiment of the lifting apparatus is disclosed in claim 3, where the base part is horseshoe- shaped with two oppositely-lying straight and parallel side parts, where each of said side parts is provided with a pressure cylinder which can displace a yoke in the vertical direction, where the yoke at each end either directly or indirectly supports the carriers and is controlled by vertical guides.
THE DRAWING
A preferred embodiment of the apparatus according to the invention will now be described in more detail with reference to the drawing, where
fig. 1 shows the lifting apparatus according to the invention seen partly in section from above and with an associated pallet,
fig. la shows an enlarged section of fig. 1,
fig. 2 shows a section along the line II-II in fig. 1,
fig. 3 shows a section along the line III-III in fig. 1,
fig. 4 shows the configuration of two cams on an apron guide for the stacking and destacking respectively of pallets according to the method,
figs. 5a-5i show the lifting apparatus in nine successive situations during the stacking of pallets, and
figs. 6a-6h show eight successive situations while
destacking with the lifting apparatus,
DESCRIPTION OF THE EMBODIMENT
The lifting apparatus according to the invention is built up around a base part which consists of two parallel members 1 arranged for mutual connection to a transverse member 3, and in such a manner that the base part, when seen from above, is in the shape of a horseshoe with equal sides. The members 1,3 can stand on a floor 5 with legs 7 in the four corners.
In the one corner the apparatus is provided with a control panel 9 at the end of an inclined stand 10.
The lifing mechanism of the apparatus is suspended on and and arranged around the members 1. Secured to each of the members 1 there are two parallel, narrow plate pieces 12, each of which at the same time is secured to the rear of its column 14 which is formed by an open, C-shaped profile. Secured to the plate pieces 12 and extending between said plates pieces there is a beam 16 which supports a vertically-standing air pressure cylinder 18. Secured to the cylinder piston there is a U-shaped beam 20 with two open, C-shaped profiles 22 hanging from its ends. The external dimensions of the profiles 22 are chosen to suit the corresponding internal dimensions of the profiles 14, thus forming a column guide with the profiles 22 as the movable part.
The profiles 22 and 14 are turned with their longitidinal openings facing in opposite directions, so that a guide 24 containing four double rollers 26 can be secured to the back of the profile 22. A carrier 28, which can be displaced in the horizontal direction, is provided between
the rollers 26. The carriers 28 are mutually connected two and two with a bar 30. The bar 30 is so long that it has free ends on which rollers 32 are provided.
Suspended on each member 1 there are two sets of identical aprons 34 which are arranged in such a manner that each of the rollers 32 is in engagement with a guide 33 welded to the one side 35 of each apron 34. The other side 36 of each apron 34 is also provided with a guide 37 having a movable part 37a which is pivotably suspended in a bearing 39. The two different sides of the apron 34 are shown in separate illustrations in fig. 4. The apron 34 is suspended, e.g. firmly screwed or inserted in slots, so that it can be taken out of the apparatus and turned so that the second side 36 can be brought into contact with the roller 32. There is hereby achieved two different patterns of movement, depending on which side of the apron 34 is being used.
Most of the lifing mechanism is surrounded by a shield 38 of sheet material. An EUR pallet 40 can be placed between the members 1 of the apparatus in such a manner that the carriers 28 can reach in under the pallet's upper boards 42.
The stacking of the pallets 40 can be carried out as shown in figs. 5a-i, where fig. 5a is the starting position in which a new pallet 40 is added to a stack of pallets 41.
In figs. 5b-5e it will be seen how the carriers 28 are moved under the influence from the rollers 32 along the forced track of the guide 37,37a during a not-shown lowering of the beam 16 by the cylinder 18. When the lowermost of the pallets 41 is resting on the pallet 40, the carriers 28 are withdrawn from the pallet 41 and thereafter, when the cylinder 18 is in its retracted
position, are moved in under the upper boards 42 on the pallet 40.
In figs. 5f-5i is shown how a not-shown extension of the cylinder 18 results in a raising of the stack, in that the movable part 37a on the guide swings to allow passage of the roller 32. A new pallet can now be introduced under the stack, cf. fig. 5a.
When destacking, a movement is effected where a stack of pallets 40,41, as shown in fig. 6a, is in a starting position when the cylinder 18 is extended. Under the influence of the guide 33, the carriers 28 are inserted and support the lowermost pallet 40, and thus the whole of the stack. The apron 34 is turned with the side 35 in engagement with the roller 32.
When the cylinder 18 is retracted, the stack is lowered as shown in figs. 6b-6d, while at the same time the guide 33 during the last part of the movement forces the carriers 28 free of the pallet 40, and the stack rests on the floor 5.
Hereafter, as shown in figs. 6e-6h, a raising of the carriers 28 is effected by a not-shown movement of the cylinder 18 and, at the last part of the movement, an insertion of the carriers 28 so that the next lowest pallet 41 is gripped by the carriers 28 and is lifted free of the lowermost pallet 40. In the position shown in fig. 6h, the pallet 40 can be removed, e.g. by a pallet truck, and the process can be repeated as shown from fig. 6a.