FI83503B - Stacking plant for veneer sheets or the like - Google Patents

Description

1 83503

Equipment for stacking veneer sheets and the like

The present invention relates to an apparatus for stacking veneer sheets and the like.

5

Known devices usually have two parallel suction belt conveyors placed on the lower surface of the suction box to perform said task. The suction belts receive stackable sheets from a suitable conveyor, for example a conventional belt conveyor extending some distance under the suction belt conveyors.

The sheets supported by these suction belt conveyors are moved above the stacking station, where the sheets are removed by the action of suction belts by rod-like members weighing on the top surface of the sheets. With the same members, the sheets are then pressed onto the stack to be formed. In order to determine the correct operation of the pressing members, the progress of the sheets to be stacked must be monitored.

20

In order to get the sheet off at the right moment from the suction belt conveyor and to stop its forward movement, i.e. to get the sheet in the right place on the bench, the movement of the pressing members must be very fast, mainly the impact movement. In known devices, this movement has continued as the same rapid movement when placing the sheet on the pink suction belts after removal. However, this movement of the presses has resulted in the weakening of the weaker veneers.

30

A substantial improvement in this rupture problem is achieved according to the invention by phasing the movement of the presses, the main details of which arrangement appear from the appended claim 1.

35

The movement of the presses is staggered so that the pressers first make a rapid, relatively short release press, which removes the veneer from the conveying effect of the conveyor belts, but after which the veneer is still subject to the suction effect of the conveyor belts. This release press must take place as quickly as possible to stop the veneer accurately, and to get it properly aligned with the stack.

After the release press, the movement of the presses continues as a slower or slower stacking movement, which can be adapted to the quality of the veneer to be stacked so that the veneer can withstand stacking without the risk of breakage. The stacking movement of the pushers may continue as a continuation of the release press immediately or after a short delay.

Within the scope of the invention, there is also an apparatus in which the release pressing and the stacking movement are performed by separate members. In this case, the starting position of the members may be the same, and they may receive the starting command at the same time, but the speed of the movements is different. The faster release pressing members 20 have had time to perform the veneer removal and stop at the position where the stacking members reach the veneer after a short delay.

The above-mentioned operating model of the stacking apparatus is applicable to conventional stacking devices, since during the release pressing step the veneer differs from the suction conveyors so little that the suction effect of the conveyors provides a sufficient pressure above the veneer to support the veneer. Due to the effect of this vacuum, the sheet detached from the transport effect of the suction belts is pressed against the pressing members and its movement stops. At this stage, the above-mentioned phased operations can be applied to the wrappers to make the sheet pink.

35

From the point of view of the precise operation of the presses, it is advantageous if, during the release pressing step, the entry of air between the veneer to be removed and the suction belt conveyor is prevented as effectively as possible. During this period, the vacuum above the veneer is maintained for as long as possible, which increases the force required for the release press, i.e. the pressure of the veneer against the pressing members. Stronger depression helps the veneer to move forward precisely.

The invention will be explained with the aid of the accompanying drawing, in which the above-mentioned hardware application is shown, in which an attempt has been made to prevent air from entering above the veneer during the removal phase. In the drawing,

Figure 1 shows a side view of a device assembly according to the invention, partly in section,

Figure 2 shows a schematic cross-section of the apparatus 20 Figure 3 schematically shows the three operating steps a, b, c of the apparatus

Figure 4 shows an alternative embodiment according to Figure 1 25

Figure 5 shows an alternative embodiment of Figure 4 in the position of Figure 2, and

Figure 6 shows the operating model of the alternative embodiment 30 corresponding to Figure 3

The apparatus shown in Fig. 1 comprises a conventional vacuum apparatus comprising a vacuum chamber and a vacuum suction apparatus 8. Mounted on the lower surface 35 of the vacuum chamber are two endless suction conveyor belts arranged in two conveying directions extending downwardly from the lower surface of the vacuum chamber.

In the known manner, the lower surface of the box structures containing the conveyor belt has a centrally running suction gap 5 4, through which a vacuum carrying the veneer is created in the space between the belts. On each side of the box structure of the conveyor belt, the press members 1 of the violin sheets are placed reciprocally. These members are solid-walled and have a suitable height so that they can form a hem structure on the long sides of the conveyor housing when lowered. printed. The pressing members also extend to the length 15 of the conveyor housing so that they can affect the entire width of the veneer sheet to be stacked.

The stacking function of the apparatus is best seen in the phase diagrams of Figure 3. In step a), the veneer sheet is entering the stacking station supported by the suction conveyor belt. When the veneer sheet is at exactly the right place, the press members 1 are pressed downwards in a rapid motion, thus reaching step b). At this stage, the pressing members 1 are still in tight sliding contact with the sides 25 of the conveyor box and likewise as tightly as possible against the sheet to be pressed down. When the suction is constantly on in the suction slot, air can flow into it only from the bottom of the conveyor housing, the pressure members and the ends of the longitudinal channel forming the veneer. In this flow state, there is thus quite a strong vacuum, as a result of which the veneer is pressed against the lower surface of the pressing members 1, but is nevertheless detached from the conveyor belt. As a result of this arrangement, the progress of the veneer is effectively stopped.

An alternative embodiment of the invention is shown in a similar manner in Figures 4-6. The difference from the embodiment shown above with the aid of Figures 1 to 3 is that instead of the members 1 performing the entire printing function, two pressing members 1a and Ib are arranged, to which part the pressing movement is divided. The release press is performed by the presses 1a, the movement of which is continued by the stacking presses Ib, as shown in Fig. 6 5.

The stopping of the veneer sheet can be enhanced by providing the lower surface of the pressing members (1; la) with a material with high abrasion friction. It is also possible to use a separate suction system on the lower surface of the press members to improve the adhesion of the sheets.

Claims (3)

6 83503 An apparatus for pinking veneer sheets and the like from a conveyor conveying veneer sheets in succession, the apparatus comprising at least one horizontal suction conveyor belt (3) connected to the suction apparatus extending downwards from the lower surface as an elongate box structure, for moving the stacking-10 above the station (6), and for pressing the veneer sheets (2) from the suction belt conveyor to the sheet stack (5), characterized in that the downward movement of the presses (1; 1a, Ib) on the veneer is two-step - a short and fast release press movement followed by a slower stacking movement. Apparatus according to Claim 1, characterized in that the apparatus has different pressing elements (1a, Ib) for the release pressing and the stacking movement. 20 Apparatus according to claim 1, characterized in that the release press and the stacking movement are performed by the same pressing members. 25