Bow transport device

Abstract

A device for transporting sheets comprises plates that together form a chain which runs along a track and is driven by a mechanism. The plates each have openings for holding the sheet on the upper surface of the respective plate by means of suction. The mechanism has at least one drive element (13) which, when the plates are driven, rotates about at least one axis (14) and engages directly with the plates (2) or with rails (10) arranged on the plates (2) in successive frictional engagement.

Description

[0001] The present invention relates to a device for transporting sheets, comprising plates which together form a chain which rotates along a track and is driven by a mechanism.

[0002] DE 10 2019 210 251 A1 describes such a device, which is used in a printing press to transport the sheets past an inkjet print head during printing. In the prior art device, the mechanism has a threaded spindle, and the plates are equipped with drivers. When the respective plate is driven, its driver engages with the threaded spindle. A disadvantage of this positive coupling between the threaded spindle and driver is that the plate supporting the sheet can jerk during engagement, which impairs print quality.

[0003] The object of the invention is to provide a device for transporting sheets which is suitable for use in a digital printing machine.

[0004] The object is achieved by a device for transporting sheets, comprising plates which together form a chain which rotates along a track and is driven by a mechanism, characterized in that the plates each have openings for holding the sheet on the upper side of the respective plate by means of suction air, and in that the mechanism has at least one drive element which rotates about at least one axis when driving the plates and engages directly on the plates or on rails which are arranged on the plates, one after the other with frictional engagement.

[0005] In the variant in which the drive element acts directly on the plates, no rails need to be arranged on the plates.

[0006] In the device according to the invention, the temporary coupling between the respective plate and the mechanism is frictionally engaged. The drive element runs so smoothly on the rail when driving the plate that no jerking occurs. Therefore, the device according to the invention is very well suited for use in a digital printing press.

[0007] The further developments of the invention described below can be implemented individually or – insofar as they are not technically mutually exclusive – in any combination: In the variant in which the drive element acts directly on the plates, the drive element can act on the side surfaces of the plates.

[0008] In the other variant, each plate may have a single rail, the mechanism may have a counter-pressure element, and the single rail may be located between the drive element and the counter-pressure element during driving.

[0009] Also in the other variant, each plate can have two rails, the mechanism can have a counter-pressure element, and the drive element and the counter-pressure element can be located between the two rails when driving.

[0010] In both variants, the drive element can be a wheel or an endless belt.

[0011] In both variants, the counterpressure element can be a wheel or an endless belt.

[0012] In both variants, the drive element can be loaded by a spring and pressed against the rails of the plates one after the other by the spring.

[0013] In both variants, the counterpressure element can be loaded by a spring and pressed against the rails of the plates one after the other by the spring.

[0014] Further developments, which can be implemented individually or - insofar as they are not technically mutually exclusive - in any combination with one another or with the previously mentioned developments, are set out in the following description of an embodiment and the associated drawing.

[0015] Showing: Fig. 1 a sheet transport device in overall view, Fig. 2 and Fig. 3 variants of a sheet transport plate of the device, with the plate shown spatially as a detail, and Fig. 4 to 12 variants of a disk drive mechanism of the device, the mechanism being shown schematically in section.

[0016] Fig. 1 shows a device for transporting sheets 1 on plates 2 in one direction 3 past a print head 4. The print head 4 is an inkjet print head. The identical plates 2 together form an endless chain 5, which rotates on an oval track 6 in one direction 7. The chain 5 has a straight section 8, to which the print head 4 is assigned. Rollers 9 are rotatably attached to the plates 2 and run on the track 6. The plates 2 each have a top side and a bottom side. The sheet 1 lies on the top side during its transport, held by suction air through openings 16 (cf. Fig. 2 and Fig. 3) in the plate 2. At least one rail 10 is attached to the underside, which runs parallel to direction 3. An electric motor 11 drives the movement of the chain 5 in direction 7 via a mechanism 12. An element 13 of the mechanism 12 comes into contact with the rail 10 of one plate 2 after the other. The element 13 is preferably located in the area of ​​section 8. The element 13 rotates around at least one geometric axis 14 and transfers its movement to the rail 10 of the respective plate 2 by friction. This plate is thereby moved parallel to direction 3. Due to the frictional engagement, the movement takes place without jerking, which would not be the case with a positive tooth engagement between the element 13 and the rail 10.

[0017] Fig. 2 shows a variant in which each plate 2 has only one monorail. This rail 10 is arranged in the center of the plate 2. The rail 10 has a recess 17 and a projection 18 at each end. At one end, the recess 17 is arranged at the top and the projection 18 at the bottom, and at the other end the arrangement is reversed. A projection of the rail 10 of an adjacent plate enters the recess 17 and the projection 18 enters a recess of a rail 10 of another adjacent plate. This interlocking of the rails 10 of the plates 2 enables the element 13 to run smoothly from one rail 10 to the other and, when passing through curved sections of the track 6, a collision-free angular position of the rails 10 of the plates 2 relative to one another.

[0018] Fig. Figure 3 shows a variant in which the rail 10, together with a parallel rail 15, forms a rail duo arranged on the underside. Both rails 10, 15 are offset equally far outwards from the center of the plate 2. With regard to the recesses 17 and projections 18, the rails 10, 15 of the variant in Fig. 3 is designed in the same way as the rail 10 of the variant in Fig. 2.

[0019] In the Fig. 2 and Fig. 3 shows that each plate 2 has pivot pins 19 and pivot holes 20. When the plates 2 are assembled to form the chain 5, the pivot pins 19 of plate 2 fit into pivot holes of an adjacent plate, and pivot pins of another adjacent plate fit into the pivot holes 20 of plate 2, which is located between the two adjacent plates within the chain 5. All plates 2 of the chain 5 are connected to one another via pivot joints 21, which consist of such pivot pins 19 and pivot holes 20. The rollers 9 are arranged coaxially with the pivot joints 21.

[0020] The Fig. 4-12 is the Fig. 1 specified viewing direction 22 based

[0021] The Fig. 4-7 show variants of mechanism 12, which are used in Fig. 2 shown variant with the single rail 10 per plate 2 can be used.

[0022] Fig. Figure 4 shows a variant in which element 13 is an endless belt 41 that rotates around wheels 42, 43 and thus around two axes. Wheel 42 is driven by motor 11 and drives belt 41. Belt 41 drives the feed motion of rail 10 and transfers the drive motion, symbolized by an arrow, from wheel 42 to wheel 43. Wheels 44, 45 are pressed against one side of rail 10 by springs 46, 47 and press the other side of rail 10 against belt 41.

[0023] Fig. Figure 5 shows a variant in which the rail 10 is pressed against wheels 52, 53 by wheels 54, 55. The wheels 54, 55 are pressed by springs 56, 57 against the rail 10, which is located between the wheels 52, 53 on one side and the wheels 54, 55 on the other side. A wheel 58 is arranged coaxially with the wheel 52 and is connected to it in a rotationally fixed manner, e.g., by a common shaft, and a wheel 59 is arranged coaxially with the wheel 53 and is connected to it in a rotationally fixed manner, e.g., by a common shaft. The motor 11 drives the wheels 52, 58. An endless belt 51, which wraps around the wheels 58, 59, transmits the drive movement from the wheel 58 to the wheel 59, with which the wheel 53 rotates. The wheels 52, 53 drive the feed movement of the rail 10 and thus of the plate 2. The element 13 is formed by the wheel 52, and there is another such element, namely the wheel 53.

[0024] Fig. Figure 6 shows a variant in which the rail 10 is pressed against wheels 62, 63 by wheels 64, 65. In this variant, the element 13 is formed by the wheel 62, and another such element is present, namely the wheel 63. The wheels 64, 65 are pressed by springs 66, 67 against the rail 10, which is located between the wheels 62, 63 on one side and the wheels 64, 65 on the other side. The motor 11 drives the wheel 62, whose drive movement is transmitted to the wheel 63 via a wheel 68. The intermediate wheel 68 bears against both wheels 62, 63.

[0025] Fig. Figure 7 shows a variant in which a belt 70 and another belt 71 are located on opposite sides of the rail 10. The endless belt 71, which forms the element 13, wraps around the wheels 72, 73. Thus, the belt 71 rotates around two axes, namely the axis 14 around which the wheel 72 rotates, and the axis around which the wheel 73 rotates. The endless belt 70 wraps around wheels 74, 75, which are loaded by springs 76, 77 and consequently press the belt 70 against one side of the rail 10. As a result, the other side of the rail 10 is pressed against the belt 71. The wheel 72 is driven by the motor 11 and drives the belt 71. The belt 71 frictionally drives the feed movement of the rail 10 and transfers the drive movement symbolized by an arrow from the wheel 72 to the wheel 73.

[0026] The variants in the Fig. 4-7, it is each characteristic that the rail 10 is clamped between at least one rotating drive element (element 13, wheel 53) and at least one rotating counter-pressure element (wheels 44, 45; 54, 55; 64, 65, belt 70) when driving the plate 2.

[0027] The Fig. 8-12 show variants of mechanism 12, which are used in Fig. 3 shown variant with the two rails 10 per plate 2 can be used.

[0028] Fig. Figure 8 shows a variant in which element 13 is an endless belt 80 pressed against rail 10 by wheels 81, 82, 83. Belt 80 wraps around wheels 82, 83. Wheel 81 is smaller than wheels 82, 83 and is positioned between them. Wheels 84, 85, 86 are pressed against rail 15 by springs 87, 88, 89. Springs 87, 88, 89 tend to move wheels 84, 85, 86 away from the other rail 10. Wheel 81 is loaded in the opposite direction by a spring 90. Wheel 82 is driven by motor 11 and drives belt 80. The belt 80 frictionally drives the feed movement of the rail 10 and transfers the drive movement symbolized by an arrow from the wheel 82 to the wheel 83.

[0029] Fig. 9 shows a variant in which a wheel 91 rests against wheels 92, 93 which rest against the rail 10. The element 13 is formed by the wheel 92, which is driven by the motor 11. The wheel 91 is a friction wheel and transmits the drive movement from the wheel 92 to the wheel 93. Alternatively, the wheel 91 or the wheel 93 can be driven by the motor 11. The wheels 92, 93 frictionally drive the feed movement of the plate 2 in directions 3 and 7 respectively. The wheels 94, 95 rest against the other rail 15 and are frictionally connected to one another via the wheel 96. The wheels 94, 95 can rotate, i.e. be frictionally driven by the passing rail 15. Alternatively, one of the wheels 94, 95, 96 can be driven by the motor 11. The wheels 92, 93 each have a rubber-elastic circumferential surface and press against the inside of the rail 10 due to their spring action.The wheels 94, 95 also each have a rubber-elastic circumferential surface and press against the inside of the other rail 15 due to their spring action.

[0030] Fig. Figure 10 shows a variant in which wheels 102, 103 are pressed against the inside of rail 10, and wheels 104, 105 are pressed against the inside of the other rail 15. Wheel 104 is in rolling contact with wheels 102, 103, and wheel 103 is in rolling contact with wheels 104, 105. Wheels 103, 104, 105 are each loaded by a spring 106, 107, 108. The forces of springs 106, 107, 108 are each split into two components by wheels 103, 104, 105. For example, wheel 105 is pressed against rail 15 by one force component of spring 107, and against wheel 103 by the other force component of spring 107. In contrast to the wheels 103, 104, 105, which are movable by springs 106, 107, 108, the wheel 102 is fixed and is designed as an abutment for the wheel 104. The wheel 102 drives the linear feed movement of the rail 10. This moves the plate 2, which is firmly connected to both rails 10, 15, in the direction 3, 7.The element 13 is formed by the wheel 102.

[0031] Fig. 11 shows a variant in which, when driving the respective plate 2, one belt 110 rests against the rail 10 and a belt 111 rests against the other rail 15. The belt 110 wraps around wheels 112, 113, and the belt 111 wraps around wheels 114, 115. The wheel 112 forms a gap 116 with the wheel 114, and the wheel 113 forms a gap 117 with the wheel 114, and a gap 118 with the wheel 115. In the gaps 116, 117, and 118, the belts 110, 111 are pressed against each other. The belts 110, 111 run in contact with each other from the gap 116 to the gap 118. The belts 110, 111 are made of a rubber-elastic material and act as preloaded springs, tending to push the rails 10, 15 away from each other. The motor 11 drives the wheel 112, which drives the belt 110. The element 13, which drives the rail 10 with frictional engagement, is formed by the belt 110. The belt 110 drives the belt 111 with frictional engagement.Alternatively, the motor 11 can additionally drive the wheel 114, which in turn drives the belt 111. The belt 110 moves the rail 10 in the direction 3, 7, and the belt 111 moves the rail 15, causing the plate 2 to move accordingly.

[0032] Fig. Figure 12 shows a variant in which an endless belt 120 forms element 13 and rests against rail 10. Belt 120 wraps around wheels 121, 122 and contacts a wheel 123 in the section between gaps 124, 125, which wheel 123 forms together with wheels 121, 122. Wheel 123 rests against the other rail 15. A wheel 126 is arranged between wheels 121, 122 and is pressed by a spring 127 against the inside of belt 120, the outside of which is consequently pressed against rail 10. Wheel 123 is arranged between wheels 128, 129, each of which is pressed against rail 15 by a spring 130, 131. The wheels 126, 128, 129 are smaller than the wheels 121, 122, 123. The motor 11 drives the rotation of the wheel 121, which drives the orbital movement of the belt 120. Through the frictional contact between the belt 120 and the rail 10, the orbital movement of the belt 120 is translated into a translation of the plate 2.

[0033] The variants of the Fig. 8 to 12, it is each characteristic that between the two rails 10, 15 at least one rotating drive element (element 13, wheel 93, 103) and at least one rotating counter-pressure element (wheel 84, 85, 86, 104, 105, 123, 128, 129, belt 111) are arranged, by means of which the rails 10, 15 are braced when the plate 2 is driven. List of reference symbols 1 sheet 2 plates 3 direction 4 Print head 5 Chain 6 lane 7 direction Section 8 9 roll 10 rail 11 Engine 12 Mechanism 13 elements 14 Axis 15 rail 16 Opening 17 Recess 18 lead 19 pivot pins 20 joint hole 21 Swivel joint 22 Viewing direction 23-24 --- 41 volumes 42 wheels 43 wheels 44 wheels 45 wheels 46 spring 47 spring 48-50 --- 51 belts 52 wheels 53 wheels 54 wheels 55 bikes 56 spring 57 spring 58 wheels 59 bikes 60-61 --- 62 wheels 63 wheels 64 wheels 65 wheels 66 spring 67 spring 68 wheels 69 --- 70 volumes 71 volumes 72 wheels 73 wheels 74 wheels 75 wheels 76 spring 77 spring 78-79 --- 80 volumes 81 volumes 82 wheels 83 wheels 84 wheels 85 wheels 86 wheels 87 spring 88 spring 89 spring 90 spring 91 bike 92 wheels 93 wheels 94 wheels 95 wheels 96 wheels 97-101 --- 102 wheels 103 bikes 104 wheels 105 bikes 106 spring 107 spring 108 spring 109 --- 110 volumes 111 Volume 112 wheels 113 wheels 114 wheels 115 bikes 116 gap 117 gap 118 gap 119 --- 120 volumes 121 bike 122 wheels 123 wheels 124 gap 125 gap 126 wheels 127 spring 128 wheels 129 bikes 130 spring 131 spring QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 210 251 A1

[0002]

Claims

[1] Device for transporting sheets (1), comprising plates (2) which together form a chain (5) which rotates along a track (6) and is driven by a mechanism (12), characterized by , that the plates (2) each have openings (16) for holding the sheet (1) on the upper side of the respective plate (2) by suction air, and that the mechanism (12) has at least one drive element (13) which rotates (14) about at least one axis when driving the plates (2) and engages directly with friction on the plates (2) or on rails (10, 15) which are arranged on the plates (2), one after the other. [2] Device according to claim 1, characterized by , that each plate (2) has a single rail (10), that the mechanism (12) has a counter-pressure element, and that the single rail (10) is located between the drive element (13) and the counter-pressure element during driving. [3] Device according to claim 1, characterized by , that each plate has two rails (10, 15), that the mechanism (12) has a counter-pressure element, and that the drive element (13) and the counter-pressure element are located between the two rails (10, 15) when driven. [4] Device according to one of claims 1 to 3, characterized by that the drive element (13) is a wheel (52, 62, 92, 102) or an endless belt (41, 71, 80, 110, 120). [5] Device according to one of claims 1 to 3, characterized by that the counter-pressure element is a wheel (44, 45, 54, 55, 64, 65, 87, 88, 89, 94, 95, 104, 105, 123, 128, 129) or an endless belt (70, 111). [6] Device according to one of claims 1 to 3, characterized bythat the drive element (13) is loaded by a spring (90, 127) and is pressed against the rails (10) of the plates (2) one after the other. [7] Device according to claim 2 or 3, characterized by that the counter-pressure element is loaded by a spring (46, 47, 56, 57, 66, 67, 76, 77, 87, 88, 89, 106, 107, 130, 131) and is pressed against the rails (10, 15) of the plates (2) one after the other.

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