JPH089430B2 - Sheet feeder - Google Patents

Abstract

In a sheet feeder with a pile reception device (2) which can be moved by means of a lift device (4) and a suction head (14) which overlaps the pile reception device (2), is adjustable in the conveying direction by means of a displacement device (27, 28) in dependence on the sheet format and is vertically adjustable by means of a lifting device (31, 32, 33), the lift device (4) allocated to the pile reception device (2) being controllable in dependence on signals emitted by a sensor (8) scanning the top front edge (7) of the pile and the lifting device (31, 32, 33) assigned to the suction head (14) being controllable in dependence on signals emitted by a sensor (21) scanning the top rear edge (20) of the pile and preferably held on the suction head (14), a high level of productivity, user-friendliness and freedom from malfunction can be achieved by making it possible to bring the suction head (14) into its lowest position when processing of a pile (3) has been completed and to lift it during the upward travel of a new pile (3) starting from its lowest position in dependence on the signals formed as the sensor (21) assigned to it runs up to the pile surface, the lifting speed of the lifting device (31, 32, 33) assigned to the suction head (14) at least corresponding to the lifting speed of the lift device (4) assigned to the pile reception device (2). <IMAGE>

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device provided with a pile mounting table movable by using a pulling device and a suction head acting on the pile mounting table from above. , It is possible to adjust the movement in the conveying direction in relation to the sheet format using a sliding device and in the vertical direction using a lifting device, in which case the pulling device assigned to the pile mounting table is the front pile. A lifting device, which is controllable in relation to the signal emitted by the sensor for detecting the upper edge and which is associated with the suction head, is preferably received by the suction head and detects the upper edge of the rear pile. Of the type that is controllable in relation to the signal emitted from the.

[0002]

PRIOR ART German Patent Application Publication No. 362
In the sheet-feeding device known from 2693, the suction head is brought to its uppermost position after the pile has been processed, i.e. during the lowering stroke of the empty pile carrier. Then, in this standby position, the suction head remains until the upper edge of the new pile reaches the working height. Only after that, the suction head is lowered, and at this time, the suction head moves closer to a proper position, that is, a working position by using a sensor for detecting the rear upper edge of the pile. This operation requires a relatively long adjustment time and thus adversely affects the achievable productivity.

[0003]

SUMMARY OF THE INVENTION The object of the invention is therefore to improve a sheet feeder of the type mentioned at the beginning such that high productivity can be achieved using simple and inexpensive means. It is to be.

[0004]

In order to solve this problem, in the structure of the present invention, the suction head can be moved to the lowest position after the completion of the pile feeding operation, and a new ascending stroke of the pile. It is possible from time to time to move from the lowest position to the desired upper position in each case on the basis of the signal emitted by the associated sensor on the upper surface of the pile, in which case a lifting head assigned to the suction head. The ascending speed of the device is the same as or higher than the ascending speed of the lifting device attached to the pile mounting table.

[0005]

The arrangement according to the invention makes it possible to bring the suction head substantially together with the pile into its working position. In this case, the adjustment time between the work position of the pile and the work position of the suction head can be saved in an advantageous manner. Moreover, unacceptable collisions are eliminated on the basis of the mutually coordinated lifting speeds of the pile and suction head. Therefore, the sheet feeding device configured as in the invention can ensure high productivity, operating comfort, failure prevention and operational reliability in an advantageous manner.

In another advantageous embodiment of the invention, the lifting speed of the lifting device associated with the suction head is greater than the lifting speed of the lifting device associated with the pile mount.
It is set to be 0 to 20% larger. With this structure, the suction head, which rises based on the signal from the sensor due to the contact between the upper surface of the pile and the associated sensor (the sensor that detects the upper edge of the rear pile), is always mounted on the pile. Since it rises more quickly than the table, a stepwise upward movement of the suction head is produced in an advantageous manner, which makes it possible to achieve particularly high operating reliability and failure protection.

In a further advantageous configuration of the invention, the sensor for detecting the upper edge of the rear pile is constructed as a press foot which is fixed to the suction head and moves up and down.
The press foot is movable to its lowest position when the suction head is stopped. With such a configuration, it is guaranteed that the sensor assigned to the suction head occupies a proper position for detecting the upper edge of the pile at the standby position of the suction head.

In still another configuration of the present invention, a sequence circuit is provided, and the sequence circuit is used to perform a vacuum load on the lifting sucker of the suction head and a supply of pressure air to the blow nozzle so that the pile and the suction head. It is configured to be operable only after the working position is obtained. By automatically connecting and connecting the vacuum and the blowing air at appropriate times in this way, it is possible to suppress the trouble in the operation and eliminate the possibility of a manual operation error.

It is also advantageous if the lifting sucker of the suction head can be moved to its lowest position when the suction head is stopped. With this configuration, the sucker of the suction head can surely occupy the starting position at the standby position of the suction head, and the sheet can be reliably caught at the time of the vacuum load at the starting position. This makes it possible to eliminate the waiting time more advantageously in combination with the sequence circuit.

[0010]

Embodiments of the present invention will now be described with reference to the drawings.

The sheet feeding device shown in the drawings has a gate-shaped frame 1 in which a pile mounting table 2 is guided so as to be vertically movable. A paper feed pile 3 can be arranged on the pile platform 2 and the paper feed piles are stacked one on top of the other, fed by means of a sheet processing machine, for example a sheet feeder of a printing machine. It is made up of a large number of sheets of paper. The pile mounting table 2 is formed by a lifting chain and has a driving motor 5
It is suspended by a pulling device 4 provided with. Paper pile 3
The front edge stopper 6 formed by a vertical strip is in contact with the front surface of the. The other pile side edges and trailing edges are open.

In the working position, the uppermost sheet must be able to advance past the leading edge stopper 6 in each case. In order to adjust this working position, a sensor 8 is provided which is arranged at a desired height and is associated with the upper edge 7 of the front pile, by means of which the motor 5 is used to drive the feed pile 3 Can be operated until is located at the desired height. For this purpose, the signal produced by the sensor 8 is processed by means of the control unit 9 into a suitable input signal for the motor 5 (from the sensor 8 to the control unit 9 and from this control unit to the motor 5). Signal conductor 10,1
1). The control device 9 is preferably configured in such a way that all the functions of the sheet feeding device can be controlled by this control device. The sensor 8 can be configured as a mechanical scanner that can cooperate with a two-point switch. In the embodiment shown, the sensor 8 is embodied as a contactless sensor, for example in the form of a reflection switch, that is to say it produces a signal which can be processed directly by means of the control device 9.

Since the pile mounting table 2 is lifted step by step by using the sensor 8 when the pile is consumed, the front upper edge 7 of the pile is always moved forward beyond the leading edge stopper 6 with the uppermost sheet. It will occupy the desired working position. When lifting a new pile, the sensor 8 also limits the upward movement. This raising movement can be carried out in two steps, ie the new pile is first brought in a quick motion to approach from the lowest position to a position just before the working position and then in a slow motion to the working position. . To switch the motor 5 from quick to slow motion, a monitoring device 12 is provided which is located below the working position and, in the exemplary embodiment shown, is located in the area of the leading edge stopper 6. This monitoring device has, for example, the shape of a photocell and is adapted to release the desired switching operation as soon as the paper feed pile 3 has passed (see signal conductor 13 leading to the control device 9). By detecting the pile leading edge 7 for pile height positioning, it is ensured that the leading edge 7 of the pile 3 occupies the correct height even if the pile surface is not flat.

A suction head 14 is arranged above the pile 3, and this suction head is taken up by a lifting sucker 15 for lifting the uppermost sheet of the pile 3 in each case, and the lifting sucker. Drag sucker 16 for forward transport of sheets 16
And have. Then, the sheet is delivered to a conveying unit that is assigned to the sheet feeding table 17 during forward conveyance and further guides the sheet. The lifting sucker 15 and the drag sucker 16 are designed to be loaded with vacuum during their operation. For this purpose, a vacuum conduit 18 is provided which leads from a vacuum source (not shown) to the suction head 14, which vacuum conduit can be interrupted by means of a switching device 19. The suction head 14 is further provided with a press foot 21 which is newly mounted on the rear upper edge 20 of the pile at each work step. Press foot 2
In the area 1 there are provided a plurality of blow nozzles 37, which are connected via a pressure air conduit 22 which can be shut off by means of a switching device 23 to a pressure air source (not shown). There is. The switching device 19; 23, for example in the form of a switching valve, is controllable by means of the control device 9, as indicated by the signal conductors 24; 25. The vacuum load on the sucker and, in this case, the lifting sucker 15 which first operates, and the pressure air load on the blow nozzle, are in this case only when the pile 3 and the suction head 14 reach their working position.

The suction head 14 is formed of a square rail fixed to the frame of the sheet feeding device, extends parallel to the sheet conveying direction, and is oriented parallel to the pile mounting table 2. It is slidably guided along the longitudinal guide 26. During each format change, the suction head 14 is shifted so that the press foot 21 collides with the rear pile upper edge 20. For movement adjustments related to the format of the suction head 14, a threaded spindle 28, which can be driven by means of an adjusting motor 27, acts, which threaded spindle is axially supported by a longitudinal guide 26. And engages the threaded sleeve of the suction head 14 which projects laterally beyond the longitudinal guide 26. The adjusted operating position may in this case be lockable by means of a tensioning device (not shown). The adjusting motor 27 is controllable via the controller 9, as indicated by the signal line 29. The control device 9 has an input device 30 for manually inputting a format.
May be provided. As a result, when a pile is exchanged, a new pile format is input. The operation of the drive motor 5 of the pulling device 4 is in this case released only when the suction head 14 is adjusted to the new format.

The working height of the suction head 14 is adjusted corresponding to the rear pile upper edge 20, which may be different from the front pile upper edge 7, as indicated by the angle α. For this purpose, the longitudinal guide 26 associated with the suction head 14 together with the associated adjusting device are threaded vertically into the plane of the pile platform 2 or the sheet transport plane and are received by the feeder frame. Are received in the respective spindles 31, and these threaded spindles can be driven by their respective bevel gear transmissions. The two bevel gear transmissions are connected to one another via a shaft 32 which is parallel to the longitudinal guides, which shaft is drivable by an associated adjusting motor 33. Two similarly drivable spindles 31 are arranged at the front end and the rear end of the longitudinal guide 26 in order to ensure a translation of the longitudinal guide 26 and thus of the suction head 14. The control of the adjusting motor 33 is controlled by the signal conductor 34.
By means of the control device 9, as indicated by, by means of a signal emitted by the press foot 21, which can be supplied via the signal conductor 35 of this control device 9.
The press foot 21 essentially forms a mechanical sensor for detecting the rear upper pile edge 20. In this case, the press foot 21 may cooperate with a two-point switch (not shown), in which case a switching signal is generated below a certain position and above a certain position. These switching signals can then be processed by the control device 9 into on / off commands for the adjusting motor 33. With such a configuration, it is possible to adapt to a difference in level between the front pile upper edge 7 detected by the sensor 8 and the rear pile upper edge 20 detected by the press foot 21.

During the feeding operation of the pile 3, the suction head 14 uses the above-mentioned device for adjusting its height, irrespective of the position of the front pile upper edge 7, the front pile upper edge 20. Always held equidistant to the rear pile top edge 20, which may be offset from.
When the empty pile mounting table 2 is moved downward after the pile 3 is fed, the suction head 14 is also brought to the lowest position. For this purpose, the adjusting motor 33 uses the control device 9 to drive the spindle 31
The threaded bush penetrated by is closed and connected until it contacts the lower stopper. The press foot 21 likewise occupies a position below it. This is achieved by the suction head 14 with the press foot 21 being stopped at its lowest position by means of the control device 9 after the end of the pile feeding operation. The same applies to the lifting sucker 15 which is desired to first come into contact with the sheet upon restart. As described above, the control for stopping the suction head 14 at the lowest position using the control device 9 is performed via the signal conductor 36. Of course, the lowering movement of the suction head 14 to the lower standby position does not have to be performed at the same time as the lowering movement of the empty pile mounting table 2, but at another time, for example, the suction head 1
4 format adjustments or when switching the suction head 14 from quick to slow motion and the like.

The suction head 14 adjusted to the new format and brought to the lowest position has a height sensor in which a press foot 21 likewise moved downwards is assigned to the rear pile upper edge 20. As a result, it stays in the standby position until it rides on the upper edge 20 of the rear pile. When the press foot 21 is raised in this case and a two-point switch associated with it is connected, this causes a closing connection signal for the adjusting motor 33, which results in the suction head 14 being lifted. However, this raising movement continues until the press foot 21 is moved again and the lower contact of the two-point switch cooperating with it is actuated. The control of the adjusting motor 33 for performing the ascending movement is performed by the suction head 1
The raising speed of 4 is such that it corresponds to, or is preferably somewhat higher than, the rising speed of the new pile lifted using the pulling device 4. It is particularly advantageous in this case if there is a speed difference of 10 to 20%. With this configuration, a stepwise upward movement of the suction head 14 is generated. This speed relationship can be applied to the ascending operation during the normal paper feeding operation.

As soon as the pile reaches its working position during the lifting movement of the new pile, that is to say the front upper edge 7 of the pile.
As soon as is detected by the associated height sensor 8, the pulling device 4 and thus the height adjusting device of the suction head 14 is stopped, whereby the pile 3 and the suction head 14 stop at their working position. As soon as this working position is obtained, the paper feeding operation can be started without further delay. For this paper feeding operation, first, the lifting sucker 15 and then the drag sucker 16 are loaded with vacuum, and blown air is supplied to the blow nozzle of the press foot 21. The loading of these vacuums and the supply of blown air are done in relation to the working position of the suction head 14, as already mentioned above. Therefore, the control device 9 is provided with an appropriate sequence circuit.

[Brief description of drawings]

1 is a side view of a sheet feeder according to the invention in partial section.

[Explanation of symbols]

1 frame, 2 pile loading table, 3 pile,
4 pulling device, 5 drive motor, 6 leading edge stopper, 7 front pile upper edge, 8 sensor, 9 control device, 10, 11 signal lead wire, 12 monitoring device,
13 signal conductor, 14 suction head, 15
Lifting sucker, 16 Drag sucker, 17
Paper feed table, 18 vacuum conduit, 19 switching device, 20 rear pile upper edge, 21 press foot,
22 pressure air conduit, 23 switching device, 24,
25 signal conductors, 26 longitudinal guides, 27 adjusting motors, 28 threaded spindles, 29 signal conductors, 30 input devices, 31 spindles, 33
Adjustment motor, 34, 35, 36 signal lead wire, 37 blow nozzle

Claims (8)

[Claims] 1. A sheet feeding device comprising a pile mounting table (2) movable by using a pulling device (4) and a suction head (14) acting on the pile mounting table from above. The suction head (14) has a sliding device (27, 2).
8) is adjustable in the transport direction in relation to the sheet format and in the vertical direction by means of lifting devices (31, 32, 33), in which case it is assigned to the pile platform (2). A lifting device (4) which is controllable in relation to the signal emitted by a sensor (8) which detects the upper pile upper edge (7) and which is associated with the suction head (14). 31, 32,
33) of the type in which the suction head (14) feeds the pile (3) in a form in which the suction head (14) feeds the pile (3) It is possible to move to the lowest position after the work is completed, and the sensor (2) belonging to the upper surface of the pile from the lowest position during the ascending stroke of the new pile (3).
Based on the signal emitted from the sensor by the contact of 1), it is possible to raise to a desired upper position in each case, in which case the lifting device (31, 32, 33) associated with the suction head (14) is raised. Speed , pile loading
Same as the rising speed of the lifting device (4) attached to the stand (2)
Sheet-fed paper feeder characterized in that it is the same or larger . 2. The lifting speed of the lifting device (31, 32, 33) assigned to the suction head (14) is
2. The sheet feeding device according to claim 1, wherein the raising speed of the pulling device (4) assigned to the pile mounting table (2) is set to be 10 to 20% higher. 3. A sensor for detecting the upper edge (20) of the rear pile is constituted as a press foot (21) fixed to the suction head (14) and moved up and down, and the press foot (14). 3. The sheet feeding apparatus according to claim 1 or 2, which is movable to the lowest position when the above) is stopped. 4. The sheet feeding device according to claim 1, wherein the lifting device (31, 32, 33) assigned to the suction head is configured as a parallel moving device. . 5. The pulling device (4) assigned to the pile mounting table (2) is adapted to the format by using the sliding device (26, 27, 28) to which the suction head (14) belongs. Claim 1 which is only operable afterwards.
The sheet feeding device according to any one of items 1 to 4. 6. A sequence circuit is provided, by means of which the vacuum load on the lifting sucker (15) of the suction head causes a sensor (8) to detect the front upper edge (7) of the pile. 6. The sheet feeding device according to claim 1, wherein the sheet feeding device is operable only after the working position of the pile (3) that has been detected is obtained. 7. The sheet feeder according to claim 1, wherein the lifting sucker (15) is movable to its lowest position when the suction head (14) is stopped. . 8. A sequence circuit is provided, by means of which the blow air supply to the blow nozzle (37) uses a sensor (8) for detecting the upper edge (7) of the front pile. 8. The method according to claim 1, wherein the operation is only possible after the detected working position of the pile (3) is obtained.
The sheet feeding apparatus according to any one of items 1 to 7.