FI121006B - Hardware for moving plate-like objects - Google Patents

Description

Hardware for moving plate-like objects

The present invention relates to an apparatus for transferring plate-like objects from a stack formed therefrom. More particularly, the invention relates to apparatus for transferring veneer sheets and the like.

For this purpose, devices based on suction grippers are used to grip the upper surface of the veneer sheet on the top of the stack and, for example, the sheet is lifted into contact with the transfer devices. The transfer means may be horizontal rollers acting in conjunction with the suction grippers and in a rotational movement corresponding to the intended feed direction. The movable sheets are lifted one by one with the suction grips to contact the roll surface of the rolls to effect a transfer action. It is also possible to pick up the veneer sheet 15 on the top of the stack with suction grips and transfer it to the conveyor for further transport, such as a conveyor belt.

The suction grips are, in principle, individual suction nozzles disposed in one or more rows of rows extending substantially over the pillar, for example transverse to the intended transfer direction. The hardware works without problems on full-width veneers, but problems are caused by the occasional stacking of layers made up of sheets narrower than full-width sheets.

An attempt has been made to assemble these incomplete sheets so that the incomplete sheets are in 25 layers side by side and cover substantially the same area in the stack as the full width sheet. With such a stack layer, the known transfer apparatus generally operates without problems, i.e., the suction grippers receive a grip on all sheets of the layer and move together from the stack, usually to the veneer drying apparatus. 1

Despite careful layering, whether hand-made or machine-made, errors occur in the layering of the layers, which may result in sheets being more or less interleaved in the layer. Interval sheets leave, supported by suction grippers, at least partly intermittently. Some sheets leaving the suction grips may prematurely detach from the suction grips and fall back into the 2 pinks, causing the pink upper layer to become mixed. Due to their partial overlap, the entrails cause problems in subsequent veneer handling equipment such as a dryer, hard-to-clog jams, underdrying, etc. A single, narrow-sliced or fallen veneer also leaves on the next full veneer the next 5 lifts, and causes overlap problems.

With the apparatus of the invention, these problems have been significantly eliminated.

The basic structure of the apparatus according to the invention is constituted by apparatus known to have 10 separate lifting means for gripping the upper surface of a displaceable plate-like object disposed in one or more rows extending in a given direction over a stack of plate-like objects. Typically, the apparatus comprises means for detecting the top surface of a stack of plate-like objects by a monitoring apparatus including at least one light source providing a substantially linear photographic pattern aligned with the lifting member row, substantially parallel thereto in each row close to the pattern based on the information that the camera device has detected from that photograph.

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The invention will be explained in detail by means of the accompanying drawing, wherein

Figure 1 shows a device according to the invention for transferring veneer sheets from a stack, Figure 2 shows a device according to the invention in operation, and

Figure 3 illustrates the effect of control of suction lifts on device operation.

Figure 4 shows an apparatus 30 according to a modified embodiment of the invention

Fig. 1 is a schematic view of a veneer sheet 10, from which the veneer sheets are removed layer by layer for further processing such as a dryer. The plywood layer is lifted from the bench by means of suction lifts 8 in the immediate vicinity of the top surface of the veneers. The elevators 3, when the suction action 4 is activated, engage the veneer or veneers of the top layer of the bench and engage them with the rolls 14. The rolls have a rotational movement in the conveying direction and take the veneer or veneers in the intended transport direction, for example for transporting the rolls 5. Figure 1 illustrates a conventional problem situation that may occur on a stack 10 in the case where a stack of unfinished veneer sheets is formed on the stack. The veneer sheets are partly interlaced. Apparatus of known structure would face a likely malfunction.

In order to avoid malfunctioning, the pumice equipment has been supplemented with auxiliary apparatus 10 according to the invention, by which the operation of the suckers can be appropriately controlled.

The suction lifts 8 are each provided with their own closing device, which in the embodiment shown is formed by a slide 7 and an actuator 6 driving it, such as a pneumatic cylinder-piston device. With the closing device, each suction lift can be combined with or separated from suction action 4.

15 The individual operation of the actuators is controlled by an actuator that is able to draw logical conclusions from the information it receives. The actuator is not shown in the drawing. Such a device is well known to those skilled in the art, and there is no need for further elaboration thereof. The activation device receives the necessary information from the camera device 1 included in the apparatus. The camera device is a line camera known in the art and has a resolution suitable for the task. The camera's field of view extends over the veneer bench and in a perpendicular direction wide enough to detect a pattern on the surface of the veneer bench.

The pattern is applied to the surface of the veneer liner in a rectangular, powerful light source 2, for which purpose a laser light source is suitable. Illumination is applied to the surface of the bench in an oblique direction, for example at an angle of 20 ° to 45 °. If the sheet 10 randomly has interleaved veneer sheets, the light wedge first faces the sheets highest in the stack, such as sheets 11 and 12 in Figure 1. The lower sheets are exposed to the light wedge away from light source 2, resulting in a stair-like pattern. Camera 2 detects this staggering. It provides information on the position of the stairs in the pattern 30 in the direction of transfer of the veneer sheets, and the extent of each step in the pattern extension direction. From this information, the activation device of the suction lifters draws logical conclusions as to which or which of the veneer sheets (Ilia 12) are on the top of the stack, and their position in the stack, transverse to the direction of transport. Based on these findings, the actuator controls the closure devices 8 to open only at the top veneer sheets 4, whereupon only these are driven by the transport rolls 14 and exit the stack, Figure 2.

An alternative apparatus implementation of the invention is illustrated in Figure 4, which apparatus 5 comprises suction devices 8, which are arranged in a plurality of parallel rows, supported by two parallel lifting beams. Each suction device in one row is controlled jointly with an adjacent suction device in an adjacent row, or independently, in principle, with the devices described in connection with the apparatus of Figures 1-3.

The apparatus according to this embodiment of the invention comprises two lighting devices 2, one 10 for each lifting beam 3, and two separate camera devices 1, respectively, for detecting a pattern on the veneer sheet stack 10. Each camera device 1 provides a signal of the structure of the photo pattern on the veneer sheet stack to the apparatus (not shown) to determine the uniformity of the top layer and to determine which pair of suction devices 8 is activated and closed.

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The beams 3 transfer the raised top plywood sheet or sheets for further transportation, such as a belt conveyor, which leads to the veneer drying apparatus.

The capacity of the equipment for further processing the veneers is insufficient for such lifting, but there is no overlapping of the veneers and the equipment is not dropped back onto the veneers. Similarly, problems in the operation of the hardware are avoided from those sources.

Claims (2)

Apparatus for moving plate-like objects (11, 12) from a strut (10) having separate lifting means (8) for suction action on the upper surface of a movable plate-like object (11, 12) disposed in one or more rows extending in a given direction over the bench, and the displacement means for moving the raised plate-like object, characterized in that the apparatus comprises means for detecting the upper surface of the plate-like object bench (10) by a monitoring device including at least one light source (2); proximity, substantially parallel thereto, at an angle to the surface of the platen, and to observe the pattern of the camera device (1), and means for controlling the suction effect of the lifting means (8) on each line adjacent the pattern based on information detected by the camera device. Apparatus according to claim 1, characterized in that the lifting means (8) comprises sliding actuator means (7; 6) for controlled opening or closing of the suction action, respectively.