FI130412B - Lifting system - Google Patents

Abstract

Lifting system in a storage for storing board stacks, the storage used in factories fabricating particle board, OSB board and MDF board, the storage having storage rows, each storage row comprising three longitudinal supports, whereby between the longitudinal supports two satellite wagons have been arranged, which satellite wagons move along longitudinal rails, and whereby the support in the middle of the three supports is located between the two satellite wagons, each satellite wagon comprising at least two lifting devices (14) and a lifting beam above the lifting devices (14). In the invention the lifting system includes a tilt saddle (15, 15’) between the lifting device (14) and the lift beam, the tilt saddle (15, 15’) allowing the lift beam to tilt according to the deformation of the lifted stacks.

Description

LIFTING SYSTEM

FIELD OF THE INVENTION

This invention relates to a lifting system in a storage for storing board stacks, the storage used in factories fabricating particle board, OSB board and MDF board, the storage having storage rows, each storage row comprising three longitudinal supports, whereby between the longitudinal supports two satellite wagons have been arranged, which satellite wagons move along longitudinal rails, and whereby the support in the middle of the three supports is located between the two satellite wag- ons, each satellite wagon comprising at least two lift- ing devices and a lifting beam above the lifting de- vices.

BACKGROUND OF THE INVENTION

The invention thus relates to a storage system for use in factories fabricating particle board, OSB board and MDF board, in which large board stacks are stored temporarily. Generally speaking, wood-based boards manufactured on a continuous-action press line are stored for a certain time in intermediate storage

N before the downstream work phases, such as sanding and

N sawing. The storage is also used for storing different

S grades of board. = 30 = The typical mass of large stacks in factories

N fabricating particle board, OSB board and MDF board is 5 40-80 tons. The typical stack height is 3-5 m, width = 1.8-3.6 m and length 5-9 m. The stacks in the storage system are transported on two wagons running on rails under the stack in the longitudinal direction of the storage, the wagons transferring a stack to rows of the storage resting on three longitudinal supports. These wagons moving in the longitudinal direction are herein called satellite wagons and they always operate in pairs. The transfer of stacks to a storage row and the fetching of stacks from a storage row occurs in such a way that a satellite wagon pair lifts a stack from the bottom surface of the stack, such that the stack de- taches from its longitudinal supports, and transports the stack to a storage row and lowers the stack onto the longitudinal supports in the storage or, when fetching from the storage, onto the supports on the main wagon (i.e. the crosswise wagon). The moving of a satellite wagon pair in a crosswise direction, i.e. from one lon- gitudinal row to another longitudinal row, occurs by driving the satellite wagon pair onto the main wagon, which then transports the satellite wagon pair to the next position, i.e. to another storage row inlet posi- tion or exit position from the storage area.

The main wagon comprises rail pairs in the lon- gitudinal direction of the storage with intervals be- tween them and height positions suited to the longitu- dinal rails in the storage.

The main wagon can comprise three fixed longi- tudinal support elements, onto the support of which the

N load being handled can be lowered. These longitudinal

N supports can be conveyor elements, with which the load

S 30 can be transferred in the longitudinal direction of the —- storage. =

N Each satellite wagon consists of a beam which 5 is lifted and lowered by two or more lifting devices, = 35 for example screw jacks or hydraulic cylinders. The stack to be lifted lies against the beam. The stack is lifted with two satellite wagons at the same time. It is inevitable that there are minor structural inaccura- cies with the rails along which the satellite wagons are driven. Installation inaccuracy of rails in vertical direction leads to inclination of satellite wagons in- wards or outwards.

Said inclination is disadvantageous because it tends to increase or decrease the lateral distance of the two lift beams. The lifted stack, due the friction force between stack and lift beams, tends to prevent sald increase or decrease of the lateral distance of two lift beams. This causes unfavorable lateral forces to the lift system and decreases the efficiency.

Disadvantageous increase or decrease of the lateral distance of the two lift beams is inevitable because lifting of the stack and lowering of the stack takes place at different places in the storage area.

Installation inaccuracy of rails in lateral direction leads to corresponding lateral forces which are directly proportional to the weight of the lifted load.

Unfavorable lateral forces caused by the inac- curacy of the rail installation are always present dur- ing lifting and transfer of the load. Due to these forces

N the conventional lifting system must be over-dimensioned

N and excess power must be installed to overcome unfavor-

S 30 able friction forces. = Document US 6213025 Bl discloses a lifting sys-

N tem in a storage for conveying and storing products. The 5 storage has storage rows, and at least one storage row = 35 comprises two longitudinal supports, whereby between the longitudinal supports satellite wagons have been ar- ranged, which satellite wagons move along longitudinal rails. Satellite wagons comprise a lifting device and a lifting platform above the lifting devices.

Document DE 102013018268 Al discloses a satel- lite wagon which comprises lifting means with suspension devices.

Documents US 5009563 A, US 6712194 Bl and DE 8714976 Ul disclose different kinds of tilting mecha- nisms in conveying devices. These tilting mechanisms are for loading and unloading products to a conveying plat- form.

SUMMARY

This invention aims to avoid the problems in- volved in the known lifting systems. The problem has been solved by an invention which is characterized by that the lifting system includes a tilt saddle between the lifting devices and the lift beam, the tilt saddle allowing the lift beam to tilt according to the defor- mation of the lifted stacks.

In one embodiment of the invention the tilt saddle is formed of an upper part and a lower part having matching spherical shapes against each other to enable the tilting of the parts in relation to each other.

S

N In one embodiment of the invention the lower

S 30 part of the tilt saddle has been mounted on a housing —- surrounding at least partly the lower part of the tilt = saddle. a

S In one embodiment of the invention the housing = 35 has been made from steel or aluminium.

O

N

In one embodiment of the invention the bottom of the housing has been arranged slidably on a slide surface of the lifting device. 5 In one embodiment of the invention the housing has been surrounded by an elastic or spring-like element enabling and also restricting a horizontal movement of the housing and thus the lift beam.

In one embodiment of the invention the elastic element is a polyurethane or rubber ring.

In one embodiment of the invention the elastic or spring-like element re-centre the housing and thus the lift beam when the beam does not carry a load.

The invention offers many advantages compared to the prior art technology. For example, the tilting function enables gentle handling of the stack of boards.

The problem of unintentional non-synchronized lift is solved by allowing the lift beam to tilt. Further, there is no lateral load or force against the lift screws (or other lifting devices). This makes the lifting devices last longer. The load is evenly distributed at any con- ditions. There is no risk of overloading during the installation, maintenance or repair. The structural in- accuracy of the rails for the satellite wagons is com-

N pensated by the tilting and floating function of the

N invention. Further, the lift beam will be self-centred

S 30 when the it is not loaded anymore. It is also possible —- to make all lifting devices, for example screw jacks, = similar to each other. This is easier for maintenance,

N and in case of emergency repair, every single screw jack © fits in any place.

N 35

N The tilting movement of the lift beam is ad- vantageous, because it allows the pressure between the lift beam and the stack to distribute evenly. This re- duces high local stress/pressure at the stack bottom surface near the edge of the lift beam. Hence, the risk of causing permanent damage to the lifted stack, i.e. the boards of the stack, is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this specification, illustrate em- bodiments of the invention and together with the de- scription help to explain the principles of the inven- tion. In the drawings:

Fig.l presents an overview of a storage system for a factory fabricating particle board, OSB board and

MDF board,

Fig.2 presents partly sectional view of a stor- age row with a pair of satellite wagons and the stack supported on the three supports.

Fig.3 presents a detail A from Fig.2 in a larger scale.

N

& x DETAILED DESCRIPTION = 30

T Fig.l thus presents an overview of a storage & system for a factory fabricating particle board, OSB x board and MDF board. The board stacks, three of which

D are seen here, are marked with the reference number 1.

S 35 There can, of course, be more board stacks but for the sake of clarity not all are presented. The board stack at the bottom edge of Fig.l is on top of a main wagon 2 moving along rails 3. This direction of movement is called the crosswise direction of the storage.

On the right-hand side of the main wagon 2 the figure presents a conveyor 4, along which the board stacks come into the storage and possibly also exit it.

The current supply of the main wagon takes place via the cable 6 of the current supply unit 7. When the crosswise wagon moves towards the current supply unit 7, the cable 6 winds onto the cable reel 5. Correspondingly, when the main wagon moves away from the current supply unit 7, the cable 6 unwinds from the cable reel 5.

Fig. 1 presents three longitudinal storage rows 8, each of which is formed from three longitudinal sup- ports 9. There can, of course, be considerably more of these storage rows 8 than three. Additionally, they can be on both sides of the main wagon 2. They are presented here now only on the left-hand side of the main wagon 2 when looking at Fig.l.

Fig. 1 also presents a wagon pair comprising two wagons 10 moving side-by-side in a longitudinal di- rection of the storage. They are referred to hereinafter as satellite wagons, and they lift and move board stacks from below. Presented in the top part of Fig. 1 is a

N satellite wagon pair that is just going under or coming

N away from a stack 1. The satellite wagon pair 10 is able

S 30 to lift a stack into the air and to transfer it either - from the main wagon 2 onto a storage row 8 or from a = storage row 8 onto the main wagon 2. A satellite wagon

N pair 10 is thus disposed in such a way that one satellite 5 wagon is located between the centermost support 9 and = 35 one of the outermost supports 9. Correspondingly, the

N second satellite wagon is located between the centermost support 9 and the other outermost support 9. Therefore,

there are always two satellite wagons side by side and they are called a satellite wagon pair 10.

Fig. 1 also presents a second satellite wagon pair, which can be seen slightly under the stack 1 on the left side. The main wagon 2 can therefore be arranged to serve more than one satellite wagon pair 10. This second satellite wagon pair is not necessarily needed but, particularly in very large storages, it adds ca- pacity. At the bottom edge of Fig. 1 a satellite wagon pair 10’ can also be seen, which can be a back-up. In other words, one satellite wagon 10’ or both satellite wagons 10’ are taken into use from it if a defect occurs in the regular satellite wagons 10 or they otherwise need servicing. In the storage system according to the invention, commissioning of a replacement satellite wagon 10’ is easy without requiring installation work or connection work.

The current supply of the satellite wagon pair 10 is arranged for example in such a way that the current supply unit 11 supplies current to busbars 12 and by these means to storage rows 8. However, the current supply of the main wagon 2 and the satellite wagons 10 are not important in this invention and could be carried out in any other suitable way.

N The storage system thus operates in practice

N in such a way that e.g. when a new board stack is brought

S 30 into the storage, it comes along the conveyor 4 to the - main wagon 2, which then transfers the stack to the = point of the correct storage row 8. Already under the

N main wagon 2, or driven there from the storage row 8 in 5 question is a satellite wagon pair 10, which lifts the = 35 board stack slightly upwards and transfers the board stack to the storage row and lowers it to the correct spot resting on the supports 9. After that the satellite wagon pair 10 can be driven back to the main wagon 2, which meanwhile could have performed another task.

In Fig.2 a storage row 8 as well as three sup- ports 9. The stack 1 has been supported on the supports 9 in this figure. Between the supports 9 there are two satellite wagons 10 driven on rails 12. Further, refer- ence number 13 refers to lift beams mounted on screw

Jacks 14 or the like lifting devices. The number of screw jacks 14 is preferably three, but at least two is necessary. With the screw jacks 14 the lift beams 13 can be lifted so that they become in touch with the bottom of the stack 1 and lift it slightly upwards so that the stack 1 is no more in contact with the supports 9. In that position the satellite wagons 10 can be driven with the stack 1 to move the stack 1 to a desired position.

In Fig.3 a detail A of Fig.? has been shown in larger scale. Reference number 16 shows a plate on which a lift beam 13 has been mounted (lift beam 13 not shown in this figure). The plate 16 has been supported on a tilt saddle 15, 15’, which consists of two parts having matching spherical shapes against each other to enable the tilting of the parts in relation to each other.

Hence, the upper part 15 of the tilt saddle is able to freely tilt in relation to the lower part 15’ of the tilt saddle according to the deformation of the lifted

N stacks 1. With a spherical bearing the tilting movement

N may take place in lateral and longitudinal direction and

S 30 anywhere between them. Of course, it would be possible —- to restrict the tilting to some directions, if neces-

E sary.

S The lower part 15” of the tilt saddle has been = 35 mounted on a housing 17 which can be made for example

N from steel or aluminium. The bottom of the housing 17 has been arranged slidably on a slide surface 18 of the lifting device, for example the screw jack 14. The slide surface 18 has a very low friction coefficient. This arrangement makes it possible for the housing 17 to slide along the sliding surface 18 within a predeter- mined distance. The sliding should take place at least in lateral direction but can also be arranged in the longitudinal direction and anywhere between them.

The housing 17 is surrounded by an elastic or spring-like element, for example a polyurethane or rub- ber ring 19. The polyurethane ring 19 or the like is slightly compressible enabling the movement of the hous- ing 17 on the slide surface 18 and thus also the movement of the plate 16 and the lift beam 13 above it. The lift beam 13 is re-centred automatically after each lift task by the aid of the polyurethane ring 19 resuming its original shape.

It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above, instead they may vary within the scope of the claims. In drawings only one possible embodiment is shown. It is also possible to arrange the slide surface 18 in another position, for example above the tilt saddle 15, 15’. It is essential

N for the invention that the slide surface 18 and the tilt

N saddle 15, 15’ are located somewhere between the lifting

S 30 device 14 and the lift beam 13, whereby the lift beam - 13 may tilt and also move in the horizontal direction

E for a predetermined distance.

R

>

S

Claims (8)

1. Lifting system in a storage for storing board stacks (1), the storage used in factories fabri- cating particle board, OSB board and MDF board, the storage having storage rows (8), each storage row (8) comprising three longitudinal supports (9), whereby between the longitudinal supports (9) two satellite wagons (10) have been arranged, which satellite wagons (10) move along longitudinal rails (12), and whereby the support (9) in the middle of the three supports (9) is located between the two satellite wagons (10), each satellite wagon comprising at least two lifting devices (14) and a lifting beam (13) above the lifting devices (14), characterized in that the lifting system includes a tilt saddle (15, 15’) between the lifting device (14) and the lift beam (13), the tilt saddle (15, 157) allowing the lift beam (13) to tilt accord- ing to the deformation of the lifted stacks (1).

2. Lifting system according to claim 1, char- acterized in that the tilt saddle (15, 157) is formed of an upper part (15) and a lower part (15) having matching spherical shapes against each other to enable the tilting of the parts in relation to each other.

3. Lifting system according to claim 1 or 2, characterized in that the lower part (157) of the tilt N saddle has been mounted on a housing (17) surrounding 5 at least partly the lower part (157) of the tilt sad- O 30 dle.

T

4. Lifting system according to claim 3, > characterized in that the housing (17) has been made S from steel or aluminiun. 1 35

O

5. Lifting system according to claim 3 or 4, characterized in that the bottom of the housing (17)

has been arranged slidably on a slide surface (18) of the lifting device (14).

6. Lifting system according to any of claims 3-5, characterized in that the housing (17) has been surrounded by an elastic or spring-like element (19) enabling and also restricting a horizontal movement of the housing (17) and thus the lift beam.

7. Lifting system according to claim 6, char- acterized in that the elastic element (19) is a polyu- rethane or rubber ring.

8. Lifting system according to claim 6 or 7, characterized in that the elastic or spring-like ele- ment (19) re-centre the housing (17) and thus the lift beam (13) when the lift beam (13) does not carry a load. N N O N < <Q I a a 00 NN © LO N O N