JPH0340843Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lift control device for a sheet stacking table that stacks and discharges corrugated cardboard sheets manufactured at the end of a corrugated board manufacturing apparatus.

A conventional device will be explained with reference to FIG. The corrugated paperboard web 1 that is continuously produced in the previous process is cut into several parts along the traveling direction, and then cut into predetermined lengths in the width direction by a cut-off 2 to form the corrugated paperboard sheets 3. The sheets 3 are discharged from the cut-off exit conveyor 4 to a shingling conveyor 5 which is operated at a slower speed than the same conveyor 4, are shingled (stacked in the shape of roof tiles), and are conveyed via a conveyor 6 onto a sheet stacking table 7. is discharged. The discharged sheets 3 hit the front plate 9, fall downward, and are stacked on the sheet stacking table 7. The sheet stacking table 7 is connected to sprockets 11, 12 and chains 13, 1 by a motor 10.
It is driven up and down via 4 and 15. The top level of the sheets stacked on the table 7 is detected by a phototube 8, and if the sheet 3 is blocking the phototube 8, the motor 10 is driven, and if it is not blocking the phototube 8, the motor 10 is stopped. In this way, the conveyor 6
The drive of the motor 10 is controlled so that the head a from the base plate is approximately constant. Reference numeral 16 denotes a limit switch that is activated when the table 7 is lowered to stop the motor 10. The corrugated cardboard sheets 3 to be manufactured are divided into several types depending on the size of the corrugations, and the thickness of each sheet differs from 3 mm, 5 mm, 9 mm, etc., and the number of sheets discharged from the conveyor 6 onto the table 7 depends on the sheet manufacturing speed and Varies greatly depending on length. However, the descending speed of the sheet stacking table 7, that is, the rotational speed of the motor 10, must be at a speed that can follow the maximum amount of sheets stacked.
In the above device, the descending speed of the table 7 is set in this way, so during normal stacking, the descending speed of the table 7 is too fast, and the stopping accuracy when the table is lowered cannot be precisely controlled, resulting in a large head a. When the head difference a increases, the falling sheets become more disordered and cannot be stacked neatly on the table.
They are stacked with their edges sticking out. In such a situation, when conveying to the next process, it is easy for the load to collapse, the protruding sheets can be damaged, and it becomes difficult to process the sheets in the next process. It can also be a hindrance.

The present invention relates to a sheet stacking table that is installed vertically movably on the downstream side of a conveyor that continuously conveys sheets and receives sheets discharged from the conveyor in a stacked manner. a sheet position detection mechanism that detects the position of the uppermost sheet stacked on the table at least three positions in the direction; and a lowering speed of the table is made slower as the lower position is detected in accordance with a sheet position detection signal of the sheet position detection mechanism. It is an object of the present invention to provide a lift control device for a sheet stacking table which is equipped with a control mechanism and eliminates the above-mentioned conventional drawbacks.

The present invention is constructed as described above, and the sheet stacking speed, which changes depending on the sheet thickness, manufacturing speed, and sheet length, is detected by the sheet position detection mechanism based on the position change of the top sheet, and the The control mechanism operates a variable speed drive mechanism to change the lowering speed of the sheet stacking table, so the sheet height can always be maintained at the best possible height, and the stacked sheets are less disturbed, eliminating the drawbacks of the conventional method. .

The invention will now be described with reference to the most preferred embodiment shown in FIGS. 2 and 3. In the figure,
25, 27, and 29 are fixedly provided sprockets. 23 is a hydraulic cylinder, and its rod tip and table 7 are connected by a chain 24 that is hung on a sprocket 25. Sprocket 2
A chain 26 is engaged with the sprocket 5 and the sprocket 27. The chain 28 is fixed to the table 7 at its intermediate position and is engaged with the sprockets 27 and 29. Therefore, table 7 is hydraulic cylinder 2
This is a solenoid valve that commands the expansion and contraction of the rod 3, and is supplied with hydraulic pressure 34 from a hydraulic source (not shown). The electromagnetic valve 33 has solenoids 30 and 31, and when the solenoid 31 is energized, a hydraulic pressure 34 is applied to the hydraulic cylinder 23, causing the rod to contract and the table 7 to rise. On the other hand, when the solenoid 30 is energized, oil is removed from the hydraulic cylinder 23, the rod is extended, and the table 7 is lowered. At this time, the opening amount of the electromagnetic valve 33 changes depending on the magnitude of the signal level supplied to the solenoid 30, the amount of oil coming out of the hydraulic cylinder 23 changes, and the descending speed of the table 7 changes.
Reference numerals 20, 21, and 22 are phototubes (sheet position detection mechanisms) provided at different heights on the side surfaces of the table 7, and when the phototubes 20, 21, and 22 are shielded from light by the sheet, the respective signals are sent to the controller. (control mechanism) 32. The controller 32 sends a low-level signal to the solenoid when a signal comes from only the phototube 20, a medium-level signal when signals come from the phototubes 20 and 21 simultaneously, and a high-level signal when signals come from all phototubes simultaneously. Send to 30. The amount of excitation of the solenoid 30 differs depending on the signal level, and the opening amount of the solenoid valve 33 is the maximum opening amount when the signal is high level, the intermediate opening amount when the signal is medium level, and the minimum opening amount when the signal is low level. becomes. In this embodiment, the phototube 22 is located 10 to 20 mm below the upper end of the conveyor 6, and the phototube 21 is
The phototube 20 is installed 20 to 40 mm below, and the descending speed of the table 7 is 60 to 60 mm at the maximum opening.
It is set to 100 mm/sec, 40 to 60 mm/sec at intermediate aperture, and 20 to 40 mm/sec at minimum aperture.

The present embodiment is constructed as described above, and the sheets 3 sent from the previous process are discharged from the conveyor 6, hit the front stopper 9, their forward force is stopped, fall downward, and are stacked on the table 7. At this time, if the stacked amount of sheets 3 is large, the phototube 22 is shielded from light, and the signal is sent to the controller 32.
A high-level signal is sent from the controller 32 to the solenoid 30, and the solenoid valve 33 opens to its maximum opening, which increases the amount of oil discharged from the hydraulic cylinder 23 and increases the descending speed of the table 7. As a result, the top surface of the stacked sheets is lowered and the phototube 22 is no longer blocked from light, and the light blocking signal from the phototube 21 sends a medium-level signal from the controller 32 to the solenoid valve 33, so that the solenoid valve 33 has an intermediate opening amount, and the table 7 The rate of descent will be slower than before. Further, when the phototube 21 is no longer shielded from light, the solenoid valve 33 becomes the minimum opening amount due to the light shielding signal from the phototube 20, and the descending speed of the table 7 becomes slower. The descending speed of the table 7 is changed in three stages according to the stacked amount of sheets, and the sheets 3 are stacked on the table 7 while keeping the height of the sheets almost constant.

In this way, according to this embodiment, the stacking speed of the sheets is detected as the stacking amount using three sets of phototubes, and the descending speed of the table is automatically changed accordingly, so that the stacking is performed while always maintaining the best head. can be raised. In addition, this reduces sheet turbulence when stacking sheets, makes it less likely that the load will collapse when conveyed to the next process, and prevents protruding sheets from getting scratched, making it easier to process the sheets in the next process. becomes.

Next, a second embodiment of the present invention shown in FIGS. 4 and 5 will be described. In this embodiment, an elongated analog phototube 35 is provided vertically. Phototube 35
consists of a light emitting element 36 and a light receiving element 36', the signal of the amount of light received by the light receiving element 36' is amplified by an amplifier 37, and an analog level signal is sent to the solenoid 30 of the solenoid valve 33 via an amplifier 38. send as The amount of excitation of the solenoid 30 is increased or decreased by an analog amount, thereby the opening amount of the solenoid valve 33 is changed steplessly, and the lowering speed of the table 7 is changed.

In this manner, in this embodiment, the descending speed of the table is automatically and steplessly controlled in accordance with the amount of sheets to be stacked, so that the head controller is even better than that of the first embodiment.

[Brief explanation of the drawing]

FIG. 1 is an explanatory side view showing the general structure of a conventional device, FIGS. 2 and 3 show an embodiment of the present invention, FIG. 2 is an explanatory view showing the overall general structure, and FIG. FIG. 2 is an enlarged explanatory view of the phototube portion, FIGS. 4 and 5 show a second embodiment of the present invention, FIG. 4 is a side view, and FIG. 5 is a front view. 3... Sheet, 6... Conveyor, 7... Elevating table, 23... Hydraulic cylinder, 20,2
1, 22, 35...Phototube, 33...Solenoid valve.

Claims (1)

[Scope of utility model registration request] In a sheet stacking table that is vertically movably provided on the downstream side of a conveyor that continuously conveys sheets and receives stacked sheets discharged from the conveyor, a variable speed drive mechanism that raises and lowers the table; a sheet position detection mechanism that detects the position of the uppermost sheet stacked on the table at three or more positions; and a control mechanism that slows down the descending speed of the table as the lower position is detected, in response to a sheet position detection signal from the sheet position detection mechanism. A lifting control device for a sheet stacking table, comprising: