EP1988040A1 - Sheet feeder for loading a transport device with folded printed sheets - Google Patents

Abstract

The feeder (1) has A-shaft (2), B-shaft (3) and C-shaft (4) that are opened to open individual signatures (7), and to deposit the signatures on a gathering chain (15). A delay element moves in the same direction as a gripper drum (13) and at a conveying speed less than a speed of the gripper drum. A press-on device is arranged upstream of a stop element to press the signatures released by the gripper against the delay element and to slow down the individual signatures upstream of the stop element to an approximate speed of the delay element before the signatures hit the stop element.

Description

The invention relates to a sheet feeder for feeding a conveyor with folded signature, with a gripper drum having at least one gripper for removing a respective sheet from a stack, with a stop device which is arranged on the circumference of the gripper drum and which has a stop on which Each sheet can be aligned with the fold advancing, and with an opening device with which the respectively aligned to the stop device sheet open and can be stored under direction reversal on the transport device.

Sheet feeders of this type are, for example, in saddle stitchers known for a long time. With such a sheet feeder, folded sheets are withdrawn individually from the pile with the gripper drum, opened and, for example, deposited on a collecting chain. At such sheet feeder the requirement is made that even with different formats and different paper trouble-free storage of the sheet is guaranteed.

An important parameter that limits the production speed is the impact velocity of the sheet at the stop. In the case of this impact, especially with thin sheets, compression and buckling of the printed sheets occur or they can spring back from the stop. This can cause interference when opening the sheet through the opening drums. This problem has long been known and there are already several proposals to solve this.

By the DE-A-30 35 497 is a sheet feeder of the type mentioned become known in which the stop is designed to be movable. The stop takes over the sheets each synchronized motion and slow them down. This is to avoid that the striking at high speed on the stop compressed sheet are compressed.

The DE-A-197 38 920 discloses a sheet feeder in which upstream of the stop a strip is arranged which forms a wedge-shaped inlet opening for the printed sheets. By a friction engagement of the sheet with the tape to stabilize the sheet to be achieved when hitting the stop.

By the EP-A-0 716 995 a sheet feeder has become known in which a guide assembly connected to a sheet stop automatically switched on and off by the supplied sheet and in which the stop is made by an impact of the printed sheet damping stop member made of rubber or a rubber alloy.

Especially with heavy press sheets, it becomes difficult even with the above proposals at high speeds, the kinetic energy sufficient to hit the bows so that no excessive, disturbing the further course of the process deformations occur.

The invention has for its object to provide a sheet feeder of the type mentioned, which allows even higher performance and still ensures safe storage of the sheet.

The object is achieved in a generic sheet feeder in that upstream of the stop pressure means are arranged, which press the released from the gripper sheet each to a decelerating member having a transport speed, but the rectified is substantially smaller than that of the gripper drum, such that the Printing sheet upstream of the stop are each slowed down substantially to the transport speed of the delay element and impinge on the stop at this reduced speed. In the case of the sheet feeder according to the invention, the speed of the printed sheet prior to the stop is thus reduced stepwise by the transfer to a retarding member at a substantially lower speed. The printed sheets can be slowed down, for example, to half the peripheral speed of the gripper drum. When hitting the sheet to the stop these sheets then only half the speed and can be held accordingly safer under control. This can in particular with thin sheet high performance can be processed without being significantly upset at the stop. Thick and heavy printed sheets, which have a correspondingly high kinetic energy, can be better controlled.

According to a development of the invention it is provided that the pressure means are arranged on the stop device. This allows a simple yet stable support of these pressure medium. At the same time, the pressure means stabilize the printed sheets in the area of the stop device.

Preferably, the pressure means have at least one pressure roller, which bears against an outer side of the delay element. This pressure roller presses the printed sheets in each case shortly before the stop on the outside of the retarder and thereby significantly reduces the transport speed of the sheet. Preferably, two spaced pressure rollers are provided. This allows a wide and secure support and stabilization of the sheets when they hit the stop.

The pressure means are arranged according to an embodiment of the invention on one arm of the stop device and pressed under tension on the delay element. Preferably, this voltage is adjustable. This allows a safe braking of the printed sheets to the lower transport speed.

According to a development of the invention, the delay element is driven by the gripper drum. This can be realized in a structurally particularly simple manner if the Drive takes place with a friction wheel, which is moved in the distance to the axis of rotation with the gripper drum. The friction wheel is driven here, for example, via a toothed belt which is in engagement with a stationary toothed belt wheel.

According to a development of the invention, the delay element has at least one ring which is mounted on the circumference of the gripper drum. The ring has an outer surface on which the printed sheets are pressed in each case before reaching the stop. A particularly safe and stable deceleration of the printed sheet is guaranteed if two such rings are provided, each having an outer surface. The outer surfaces have a radius that is equal to or less than the radius on which the grippers transport printed sheets to the stop device.

The printed sheets are preferably gripped simultaneously by two grippers, which are each arranged directly next to said outer surfaces of the rings. The distance between said outer surfaces is thus equal to or insignificantly smaller than the distance of the pairs arranged gripper.

According to a development of the invention, the delay orifice has at least one endless band. This endless belt is thus arranged at least in the region of the stop device and driven at a speed which is substantially smaller than the transport speed of said gripper.

A deceleration of the printed sheets to a particularly low transport speed is possible if, according to a development of the invention, the delay element has two or more than two elements which have different transport speeds. The printed sheets can then be braked over two or more stages to a particularly low speed. Thus, the impact speed of the sheet on the stop and thus the risk of damage to the sheet can be further reduced.

The sheet feeder is particularly suitable as a feeder for a gathering chain, but it can also be loaded with other transport devices such a sheet feeder.

Fig. 1

eine Seitenansicht eines erfindungsgemässen Bogenanlegers, wobei aus zeichnerischen Gründen eine Seitenwand des Gehäuses weggelassen ist,

Fig. 2

ein Schnitt durch den Bogenanleger entlang der Linie II-II der Figur 1,

Fig. 3

ein Schnit durch den Bogenanleger entlang der Linie III-III,

Fig. 4

eine räumliche Ansicht eines Teils des erfindungsgemässen Bogenanlegers,

Fig. 5

eine Teilansicht des erfindungsgemässen Bogenanlegers und

Fig. 6

eine Teilansicht eines Bogenanschlages gemäss einer Variante,

Fig. 7

ein Diagramm zur Erläuterung der Geschwindigkeitsänderung der Druckbogen beim Transport auf der Greifertrommel.

Embodiments of the invention are explained below with reference to the drawings. This shows:

Fig. 1

a side view of an inventive sheet feeder, wherein for illustrative reasons, a side wall of the housing is omitted,

Fig. 2

a section through the sheet feeder along the line II-II of FIG. 1 .

Fig. 3

a cut through the sheet feeder along the line III-III,

Fig. 4

a spatial view of a portion of the inventive sheet feeder,

Fig. 5

a partial view of the inventive sheet feeder and

Fig. 6

a partial view of a sheet stop according to a variant,

Fig. 7

a diagram for explaining the change in speed of the sheets during transport on the gripper drum.

The sheet feeder 1 has according FIG. 1 a housing 5, which has spaced-apart side plates 5a, of which in FIG. 1 only one is shown. In housing 5, a so-called A-shaft 2 is mounted, which is driven by a drive device, not shown here about an axis of rotation 11 in the direction of the arrow 9 and thus in a clockwise direction. With the A-wave 2 are each of a sheet stack 8, which may also be arranged in the housing 5, a folded sheet 7 withdrawn and transported with a fold 7 a ahead in the direction of arrow 9 to a stop device 32. The stop device 32 is set to the format of a printing sheet 7 and forms with a stop element 10 a stop for the occasional folded printed sheet 7. The voltage applied to the fold 7a on the stop element 10 printed sheet 7 are of a B-wave 3 and a C-wave 4th taken and opened in a conventional manner and stored on a transport device, eg. A collection chain 15. On the gathering chain 15, the saddle-shaped lying printing sheet 7 are transported parallel to the axis of rotation 11 and added to further processing further device not shown here. The B-wave 3 and the C-wave 4 can in known Be wise and therefore will not be explained here. These waves can also be replaced by another suitable device with which the printed sheets 7 can be opened and stored on a transport device.

The gripper drum 13 has according FIG. 2 two spaced-apart wheels 13 a and 13 b, which are fixedly connected to a shaft 19. This shaft 19 is mounted on the housing 5 and is driven by a toothed belt wheel 37. At each of the two wheels 13a and 13b are located at the same distance on the circumference of three grippers 6, each having a gripper arm 6a and a gripper pad 6b. The grippers 6 are arranged in pairs, for example on the outside, ie they have a greater distance in the direction of the axis of rotation 11 than the two wheels 13a and 13b. It is also conceivable that the grippers 6 of at least one of the wheels 13a and 13b are arranged between the wheels 13a and 13b. The gripper arms 6a are each attached to a control shaft 31 which is connected to arranged in a housing 33 control cams, and can be pivoted with this for gripping a respective printed sheet 7 in a known manner.

The FIG. 4 shows above two open gripper 6, while the remaining grippers 6 are closed. In the closed state is according to FIG. 1 between each two gripper arms 6 and two gripper pads 6b a sheet 7 held in the region of the fold 7a. With the gripper drum 13, three sheets 7 can be transported per revolution. The gripper drum 13 can also be designed so that they are only for the transport of a printed sheet 7 or for more than three sheet 7 per revolution is formed. The grippers 6 shown here are merely preferred embodiments for gripping means.

On the two wheels 13a and 13b, a ring 14 is mounted in each case, which is driven by a drive 34. The two rings 14 are driven so that their peripheral speed is substantially smaller than that of the gripper drum 13. The peripheral speed of the two rings 14 is, for example, half as high as the peripheral speed of the gripper drum 13. The outer diameter of the rings 14, as in Fig. 3 shown selected so that it is equal to or smaller than the diameter on which the grippers 6 holding the printing sheet 7 rotate about the axis of rotation 11.

The drive 34 has a toothed belt wheel 18 which is mounted on the shaft 19 and which is connected to a holder 38 fixed to the housing 5. The toothed belt wheel 18 is thus stationary with respect to the housing 5. At a distance from the shaft 19, a further toothed belt wheel 21 is arranged, which is rotationally fixedly connected to a shaft 16 which is fixed in parallel and at a distance from the shaft 19 with a holder 17 on the gripper drum 13. To the toothed belt wheels 18 and 21, a toothed belt 20 is placed, which is tensioned with a belt tensioner 22. Rotates the gripper drum 13 on the A-shaft 19 about the axis 11, the shaft 16 moves like a planet on a circular path about the axis 11. By the engagement of the toothed belt 20, the shaft 16 is rotated simultaneously about its axis. To drive the two rings 14, two friction wheels 24 are mounted on the shaft 16 at a distance from each other, which according to the FIG. 2 each pressed against an inner surface 25 of the rings 14.

By appropriate choice of the transmission ratios of the toothed belt wheels 18 and 21 and the diameter of the friction wheels 24 and the inner diameter of the inner surface 25 of the rings 14, the peripheral speed and the direction of rotation of the rings 14 can be influenced. Preferably, and for example, the gear ratios are selected so that the peripheral speed of the two wheels 14 is about 20 to 40% of the peripheral speed of the gripper drum 13. Instead of the frictional transmission of the rotational movement of the wheels 24 on the rings 14 is by another transmission, for example. By means of toothing conceivable. Also conceivable is an embodiment in which the rings 14 are driven separately, for example with a suitable motor.

The gripper drum 13 transports the printed sheet 7 withdrawn from the stack 8 in each case with preferably constant transport speed v ₁ to the stop device 32. Shortly before each fold 7a (FIG. FIG. 1 ) of the printing sheet 7 impinges on the stop element 10, the corresponding two grippers 6 release the sheet 7. Substantially simultaneously with the opening of the corresponding gripper 6, the sheet 7, as in FIG FIG. 2 shown pressed with two pressure rollers 12 each having an outer surface 30 of the two rings 14. The printed sheet 7 is braked by appropriate friction on the outer surfaces 30 to the peripheral speed v _{2 of} the two rings 14 and thereby loses kinetic energy. The pressing force of the two pressure rollers 12 can by a setting device 35 (FIG. FIG. 1 ) of the stopper 32 are adjusted. The contact pressure can be changed, for example, by means of a piston, which is acted upon by adjustable compressed air. A design is also conceivable the desired contact pressure is generated by a spring. By adjusting the contact pressure, the friction between the sheet 7 and the outer surfaces 30 and thus the negative acceleration of the sheet 7 can be adjusted.

The sheet 7 is then transported further with a corresponding reduced speed until the fold 7a rests against the stop element 10 and the printed sheet 7 is aligned accordingly. The stop element 10 is preferably made of a damping material, which largely prevents a jumping back of the printed products. The folds 7a parallel to the free edges of the sheet 7, are now detected by the A-wave 2 and the B-wave 3 and the sheet 7 is opened so that it according to FIG. 1 can be stored on the gathering chain 15. The printed sheet 7 is thereby pulled out of the stop device 32 under direction reversal.

Before the printing sheet 7 is caught and opened by the A-shaft 2 and the B-shaft 3, the sheet 7 remains aligned on the stop element and remains aligned by the frictional force on the two rings 14 and the stop element 10. When pulling out the sheet 7 from the stopper 32, this frictional force is overcome.

The two rings 14 form with the pressure rollers 12, a delay member 36, which transport the sheets 7 in the same direction as the gripper 6, but at a substantially reduced speed.

The FIG. 6 shows a sheet feeder 1 ', which is basically like the sheet feeder 1 is formed, but by a Delay member 36 'differs according to a variant. Instead of the two rings 14, however, an endless belt 26 is provided here, which is guided over deflection rollers 27 and driven by a drive roller 28. With a tension roller 29, the band 26 is stretched. As can be seen, the band 26 is arcuately guided in the region of the deflection rollers 27 and extends upstream and downstream of the stop element 10. The band 26 is preferably driven at a constant speed v ₂ . The speed v ₂ corresponds to the speed of the delay member 36. However, this speed v ₂ is not mandatory, but can also be controlled variable. For example. For example, the speed v _{2 could} be controlled so that it is reduced during the transport of the printing sheet 7 to the stop element 10, so that the speed of the printing sheet 7 is further reduced when hitting the stop element 10.

The in the FIG. 6 not shown gripper drum 13 transports a withdrawn from the stack 8 sheet 7 as described above. Before the stop element 10 of the sheet 7 is detected by the pressure roller 12 and pressed against the belt 26. At the same time, the gripper 6, which has hitherto transported the printed sheet 7, is opened and thus the printed sheet 7 is transferred to the belt 26 for transport. As with the sheet feeder 1, the lower transport speed of the belt 26 reduces the transport speed of the printing sheet 7. Even with the sheet feeder 1 'is a delay over several stages possible. Accordingly, then several bands 26 and pressure rollers 12 would be provided. The detection of the printed sheet 7 with the B-shaft 3 and the C-shaft 4 and the drop to the gathering chain 15 or the transport device takes place as explained above.

Instead of the pressure roller 12 may also be another suitable pressure element, for example. Also be provided an endless belt. Also possible is a design with two mutually spaced bands 26 and correspondingly two pressure rollers 12. The sheets 7 are then detected according to two bands 26 and two pressure rollers 12 and transported to the stop element 10.

The speed profile during transport of the printed sheets 7 in the region of the stop device 32 will be described below with reference to the diagram FIG. 7 and the representation according to FIG. 5 explained in more detail. In the FIG. 5 a first angular position α _{1 is} shown in which the gripper 6 engaging the printed sheet 7 opens. At the angle α ₁ , the corresponding printed sheet 7 is pressed against the rings 14 substantially simultaneously with the opening of the gripper 6 and thus the transport speed of the printing sheet 7 is delayed from the speed v ₁ to the speed v ₂ . This is in the FIG. 7 shown by way of example with a curve K2. From the existing at the first angular position α ₁ peripheral speed v _{1 of} the corresponding sheet 7 is delayed up to a second angular position α ₂ to the peripheral speed or transport speed v ₂ . At an angular position α ₃ , the printed sheet 7 now hits the stop element 10 with the fold 7a and is decelerated by it to the peripheral speed v ₀ and thus to the zero speed.

In FIG. 7 the curve K3 shows a speed course of a sheet 7, which is transported with a delay member 36 or 36 ', in which the transport speed is controlled variably by a cam control or a motor. When transporting the corresponding printed sheet 7, the velocity of the retarding member 36 or 36 'is reduced from the angular position α ₁ to the angular position α ₂ with the mentioned control or the motor. This makes it possible to further reduce the impact velocity of the printed sheets 7 on the stop element 10. In the FIG. 4 It can be seen that the corresponding impact velocity is still significantly smaller than the velocity v ₂ . As already mentioned above, such a delay is also possible over several stages.

In the FIG. 7 shows the curve K1 the speed curve in a sheet feeder according to the prior art, in which the printed sheets 7 impinge on the stop member 10 at the angular position α ₃ without delay. The printed sheets 7 are thus abruptly decelerated at the speed v _{1 of} the gripper drum 13 on the stop element 10 to a standstill or up to the peripheral speed v ₀ .

Claims (9)

Sheet feeder for feeding a transport device (15) with folded signature (7), with a gripper drum (13) having at least one gripper (6) for removing a respective printing sheet (7) from a stack (8), with a stop device (32 ), which is arranged on the circumference of the gripper drum (13) and which has a stop (10) on which printing sheet (7) in each case with the fold (7 a) are aligned in advance, and with an opening device (3, 4), with the the printed sheets (7) aligned respectively on the stop device (32) are opened and reversible on the transport device (15) can be deposited, characterized in that pressure means (12) are arranged upstream of the stop (10), which from the gripper (6) Released printed sheet (7) in each case to a delay member (36, 36 '), which is a transport speed which is rectified and substantially smaller than that of the gripper drum (13), such that the printing sheets (7) are decelerated upstream of the stop (10) respectively substantially to the transport speed of the retarder (36, 36 ') and at a reduced speed hit the stop (10). Sheet feeder according to claim 1, characterized in that the pressure means (12) are associated with the stop device (32). Sheet feeder according to Claim 1 or 2, characterized in that the pressure means (12) have at least one pressure roller (12) which can be pressed against an outer surface (30) of the retarding member (36, 36 '), or a band. Sheet feeder according to one of claims 1 to 3, characterized in that the pressure means (12) two opposing, respectively pressure rollers (12) or pressure belts which can be pressed against a retarder (36, 36), each of which presses a printed sheet (7) at least approximately simultaneously against the retarding member (36, 36 '). Sheet feeder according to one of claims 1 to 4, characterized in that the delay element (36, 36 ') is drive-connected to the gripper drum (13). Sheet feeder according to claim 5, characterized in that the delay element (36) has at least one ring (14) which is mounted concentrically to the gripper drum (13). Sheet feeder according to claim 6, characterized in that the retarding member (36) has two opposing rings (14) provided with the outer surface (30). Sheet feeder according to one of claims 1 to 4, characterized in that the delay element (36 ') is formed by at least one endlessly circulating belt (26). Sheet feeder according to claim 8, characterized in that the endless belt (26) in the region of the stop device (32) has an arcuately guided section.

Images