Tensioning device

Abstract

The present invention relates to a device for tensioning sheets in a feeder, which includes a transport plane defined by a feed table, along which the sheets are transported in a transport direction, and further includes a first suction cup (5) having a first geometric axis of rotation (R1) and a second suction cup (6) having a second geometric axis of rotation (R2), wherein, when sucking the sheet, the first suction cup (5) rotates counterclockwise about the first axis of rotation (R1) and the second suction cup (6) rotates clockwise about the second axis of rotation (R2). The first axis of rotation (R1) and the second axis of rotation (R2) converge with respect to each other at an angle (α) in an imaginary plane (E) that is inclined with respect to the transport plane (F).

Description

Technical Field

[0001] The present invention relates to a device for tensioning a sheet in a feeder, the device comprising a transport plane defined by a feed table, along which the sheet is transported in a transport direction, the device further comprising a first suction cup having a first geometric axis of rotation and a second suction cup having a second geometric axis of rotation, wherein, when sucking the sheet, the first suction cup rotates counterclockwise about the first axis of rotation and the second suction cup rotates clockwise about the second axis of rotation. Background Art

[0002] DE 10 2021 118 805 B3 describes such a tensioning device. Summary of the Invention

[0003] The object of the present invention is to provide another tensioning device.

[0004] This object is solved by a device for tensioning a sheet in a feeder, the device comprising a transport plane defined by a feed table, along which the sheet is transported in a transport direction, the device further comprising a first suction cup having a first geometric axis of rotation and a second suction cup having a second geometric axis of rotation, wherein, when sucking the sheet, the first suction cup rotates counterclockwise about the first axis of rotation and the second suction cup rotates clockwise about the second axis of rotation, characterized in that the first axis of rotation and the second axis of rotation converge in a virtual plane that is inclined with respect to the transport plane at an angle to each other.

[0005] The tensioning device according to the present invention avoids the sheet bulging upwards and ensures a flat placement.

[0006] The following improvement options of the tensioning device according to the present invention can be combined with each other arbitrarily:

[0007] The plane can descend at an angle inclined downwards when observed in the transport direction.

[0008] The first axis of rotation and the second axis of rotation can converge downwards in the plane.

[0009] The first suction cup can be arranged on the left side of the draw rail when observed in the transport direction, and the second suction cup can be arranged on the right side of the draw rail when observed in the transport direction.

[0010] The first suction cup and the second suction cup can be driven respectively by a helical gear transmission mechanism.

[0011] The first suction cup and the second suction cup can be synchronized with the sheet transport rhythm ( )Driven synchronously and rotating exactly 360° per sheet transported (Umdrehung). Description of the Drawings

[0012] Other improvement solutions are derived from the following embodiments and the description of the drawings.

[0013] The drawings show:[[]]END]]

[0014] Figure 1 : Feeder;

[0015] Figure 2 : Tensioning device of the feeder;

[0016] Figure 3 : Partial side view of the tensioning device; and

[0017] Figure 4 : Partial rear view of the tensioning device. Detailed Description of the Invention

[0018] Figure 1 A printing press with a feeder 1 for sheets B is shown. The feeder 1 has a feed table 2, at the end of which a pneumatic pull rail 3 and a tensioning device 4 are arranged.

[0019] Figure 2 The pull rail 3 and the tensioning device 4 are shown as seen in the line of sight direction II. The tensioning device 4 includes a first suction cup 5 and a second suction cup 6, and the pull rail 3 is arranged between the first suction cup 5 and the second suction cup 6. The first suction cup 5 is arranged on the left and rotates counterclockwise when viewed in the transport direction T of the sheet B. The second suction cup 6 is arranged on the right and rotates clockwise. The first suction cup 5 and the second suction cup 6 are driven synchronously with the sheet transport rhythm of the feeder 1 and rotate exactly one full turn (360°) per sheet B transported.

[0020] Figure 3 The first suction cup 5 is shown as seen in the line of sight direction III,[[]]END]] Figure 4 The first suction cup 5, the second suction cup 6 and the shaft 7 are shown as seen in the line of sight direction IV. The first suction cup 5 and the second suction cup 6 are driven by the shaft 7 and are respectively connected to the shaft 7 by a helical gear transmission mechanism 8.

[0021] The two helical gear drive mechanisms 8 each include a first gear 9 located on the shaft 7 and a second gear 10 located on each of the first suction cups 5 and the second suction cups 6. The first gear 9 meshes with the second gear 10. The first suction cup 5 has a first axis of rotation R1, which is also the axis of rotation of the first gear 9 of the first suction cup 5. The second suction cup 6 has a second axis of rotation R2, which is also the axis of rotation of the first gear 9 of the second suction cup 6. The shaft 7 has a third axis of rotation R3, which is also the common axis of rotation of the two second gears 10.

[0022] The first axis of rotation R1 and the second axis of rotation R2 are each oriented obliquely (non - orthogonally intersecting) with respect to the third axis of rotation R3 and converge downward at an acute angle α in an imaginary plane E. The plane E slopes downward at an acute angle β with respect to the transport plane F of the sheet B in the transport direction T. The plane E intersects the transport plane F on a horizontal line that is orthogonal to the transport direction T.

[0023] Openings 11 are provided in the first suction cups 5 and the second suction cups 6, and these openings 11 are loaded with vacuum from the inside of the disks to adsorb the sheet B when it is laterally tensioned and moved toward the front stop 12 (see Figure 2 ). These openings 11 are only located within the circumferential angular sections (less than 360°) of each of the first suction cups 5 and the second suction cups 6.

[0024] List of reference numerals

[0025] 1 Feeder

[0026] 2 Feeding table

[0027] 3 Pulling rail

[0028] 4 Tensioning device

[0029] 5 First suction cup

[0030] 6 Second suction cup

[0031] 7 Shaft

[0032] 8 Helical gear drive mechanism

[0033] 9 First gear

[0034] 10 Second gear

[0035] 11 Opening

[0036] 12 Front stop / front mark (Vordermarke)

[0037] B Sheet

[0038] E Plane

[0039] F Transmission Plane

[0040] R1 First Rotation Axis

[0041] R2 Second Rotation Axis

[0042] R3 Third Rotation Axis

[0043] T Conveying Direction

Claims

1. An apparatus for tensioning a sheet in a feeder, the apparatus comprising a conveying plane (F) defined by a feed table (2), a sheet (B) being conveyed along the conveying plane in a conveying direction (T), the apparatus further comprising a first suction cup (5) having a geometric first rotation axis (R1) and a second suction cup (6) having a geometric second rotation axis (R2), wherein, When sucking the sheet (B), the first suction cup (5) rotates counterclockwise about the first rotation axis (R1), and the second suction cup (6) rotates clockwise about the second rotation axis (R2). It is characterized in that the first rotation axis (R1) and the second rotation axis (R2) converge away from the sheet (B) in a direction towards each other at an angle (α) in an imaginary plane (E) that is inclined with respect to the conveying plane (F).

2. The device according to claim 1, It is characterized in that when observed in the conveying direction (T), the plane (E) descends obliquely downward at an angle (β).

3. The device according to claim 1 or 2, It is characterized in that the first rotation axis (R1) and the second rotation axis (R2) converge downward in the plane (E).

4. The device according to claim 1 or 2, It is characterized in that when observed in the conveying direction (T), the first suction cup (5) is arranged on the left side of the pulling rail (3), and when observed in the conveying direction (T), the second suction cup (6) is arranged on the right side of the pulling rail (3).

5. The device according to claim 1 or 2, It is characterized in that the first suction cup (5) and the second suction cup (6) are respectively driven by a helical gear transmission mechanism (8).

6. The device according to claim 1 or 2, It is characterized in that the first suction cup (5) and the second suction cup (6) are driven synchronously with the sheet conveying rhythm and rotate exactly 360° for each sheet (B) conveyed.

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