Vacuum suction wheel

Abstract

A vacuum suction wheel capable of stably discharging a sheet in a discharge section of a sheet-fed printing press is provided. The vacuum suction wheel includes a suction inner tube orthogonal to a conveying direction of a single sheet in the discharge section of the sheet-fed printing press and capable of making an internal space negative pressure, and a suction outer tube (32) located radially outside the suction inner tube and rotating in a circumferential direction with respect to the suction inner tube. A plurality of planar portions (321...321) are provided at intervals in the circumferential direction at an outer circumferential portion of the suction outer tube (32). Each planar portion (321) has a planar surface (3211) with a smaller radius than a portion sandwiched in the circumferential direction by the planar portion. Each planar portion (321) has a plurality of suction holes (323...323) that open in a manner not to contact a circumferential end edge of the planar surface (3211) and are capable of communicating with the internal space of the suction inner tube.

Description

Technical Field

[0001] This invention relates to a vacuum suction wheel, which is disposed in the discharge section of a sheet-fed printing press and is used to reduce the conveying speed of sheet-like materials. Background Technology

[0002] For example, a vacuum suction wheel is described in Patent Document 1. The vacuum suction wheel described in Patent Document 1 has an outer suction tube (the "rotating suction shroud" in Patent Document 1) with multiple holes, which extends in the width direction of the single sheet of paper being conveyed to the discharge section. The outer suction tube is a cylindrical tube. The outer suction tube is connected to a vacuum pump, and by driving the vacuum pump, the multiple holes generate a suction force. A paper discharge clamp is provided on the discharge section to clamp and convey the single sheet of paper. To make the tangential velocity lower than the moving speed of the paper discharge clamp, a driving force is applied to the outer suction tube and it is rotated, causing the outer suction tube (specifically, the multiple holes it has) to attract the single sheet of paper released from the paper discharge clamp, thereby reducing the conveying speed of the single sheet of paper, i.e., the discharge speed.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Patent No. 3332684 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, because the existing vacuum suction wheel is tubular, its outer circumference is a curved surface with a constant curvature. On the other hand, the surface of the sheet (single sheet of paper) is flat. Therefore, since the curved surface (vacuum suction wheel) is in contact with the flat surface (sheet), the adhesion between the two can only occur in a roughly linear manner, making effective suction difficult. Consequently, it is difficult to decelerate the sheet using the vacuum suction wheel. Moreover, this can also lead to poor sheet ejection.

[0008] In particular, when using thick sheets such as thick paper, the sheets are heavier than thin sheets, and their surfaces hardly deform along the outer circumference of the vacuum suction wheel, making them even more difficult to suction. When using such thick sheets, for example, the sheet ejection speed is set to a low speed, which can lead to reduced printing efficiency.

[0009] In view of the above-mentioned problems, the present invention addresses the technical issue of providing a vacuum suction wheel capable of stable sheet discharge in the discharge section.

[0010] Technical solutions for solving technical problems

[0011] The vacuum suction wheel of the present invention is provided in the discharge section of a sheet-fed printing press. The vacuum suction wheel rotates while simultaneously attracting the sheet material on its outer periphery, thereby reducing the conveying speed of the sheet material. The vacuum suction wheel is characterized by having an inner suction tube and an outer suction tube. The inner suction tube is a straight tube whose axial direction is orthogonal to the conveying direction and is fixed in the discharge section, capable of creating a negative pressure in its internal space. The outer suction tube is a straight tube located outside the diameter of the inner suction tube and is rotatable relative to the inner suction tube in the circumferential direction. On the outer periphery of the outer suction tube, a plurality of planar portions are provided at intervals in the circumferential direction. Each of these planar portions has a plane orthogonal to the radial direction, the radius of which is smaller than the portion sandwiched by the planar portions in the circumferential direction. Each of the planar portions has a plurality of suction holes that open in a manner not to contact the circumferential edge of the plane, and these suction holes are capable of communicating with the internal space of the inner suction tube.

[0012] According to the above structure, the flat part abuts against the sheet of paper in a plane, thereby making it easier to slow down the sheet of paper compared to a structure where the curved surface (suction tube) and the flat surface (sheet) abut against each other.

[0013] In addition, the plane can be formed continuously in the axial direction.

[0014] According to the above structure, since the continuous plane in the axial direction uniformly abuts against the sheet, the sheet can be effectively attracted.

[0015] Alternatively, the outer periphery of the suction tube may be configured such that the planar portion and the circumferential portion are alternately arranged in the circumferential direction, and the circumferential portion has a curved surface with a constant radius.

[0016] Based on the above structure, for example, by chamfering the raw material, i.e., the round tube, an attraction outer tube can be easily obtained.

[0017] Invention Effects

[0018] According to the present invention, since the planar portion of the suction tube abuts against the sheet in a planar manner, compared to a structure where the curved surface (suction tube) and the planar surface (sheet) abut against each other, it is easier to decelerate the sheet by making it fit tightly against the suction tube. Therefore, stable sheet discharge can be achieved at the discharge section. Attached Figure Description

[0019] Figure 1 This is a simplified diagram illustrating the structure around the discharge section of a sheet-fed printing press equipped with a vacuum suction wheel according to one embodiment of the present invention.

[0020] Figure 2This is a perspective view of the vacuum suction wheel.

[0021] Figure 3 This is a cross-sectional view showing the vacuum suction wheel cut radially.

[0022] Figure 4 This is a side view showing the suction outer tube in the vacuum suction wheel.

[0023] Figure 5 (a) is Figure 4 A cross-sectional view along the VV direction. Figure 5 (b) is Figure 5 Enlarged view of the main part of (a).

[0024] Figure 6 This is a side view of the suction outer tube in a vacuum suction wheel, illustrating another embodiment of the present invention.

[0025] Figure 7 yes Figure 6 A cross-sectional view taken along the VII-VII direction.

[0026] Figure 8 yes Figure 6 A cross-sectional view observed along the VIII-VIII direction. Detailed Implementation

[0027] The following shows the respective attachments. Figure 1 The vacuum suction wheel 3 of two embodiments of the present invention will be described below.

[0028] like Figure 1 As shown, the vacuum suction wheel 3 of this embodiment, like the conventional vacuum suction wheel, is provided in the discharge section (paper discharge section) 2 of the sheet-fed printing press 1. Furthermore, this vacuum suction wheel 3 has the following function: while rotating to allow the sheet of paper S, which is being transported to the discharge section 2 as a sheet material, to be conveyed in the transport direction, the vacuum suction wheel 3 attracts the sheet of paper S from its outer periphery, thereby reducing the transport speed of the sheet of paper S. This vacuum suction wheel 3 constitutes part of the vacuum suction device in the discharge section 2 that reduces the transport speed of the sheet of paper S.

[0029] The vacuum suction wheel 3 is disposed in the paper discharge clamp 21 in the discharge section 2. Figure 1The movement trajectory of the plurality of paper feed clamps 21 located on the paper feed chain 22 (the positions of which are shown in circles) is illustrated below, with each clamp clamp 21 holding a single sheet of paper S for transport. The paper feed clamps 21 release the single sheet of paper S in front of (downstream of) the vacuum suction wheel 3 in the transport direction. Furthermore, the release position of the single sheet of paper S can be adjusted. The released single sheet of paper S moves in the transport direction by inertia, while simultaneously descending due to the downward airflow generated by the fan (not shown) located in the discharge section 2. During this inertial movement, the single sheet of paper S is attracted by the vacuum suction wheel 3 and thereby decelerates. As for the decelerated sheet S, its front edge in the conveying direction contacts the front guide 23 provided in the discharge section 2, its rear edge in the conveying direction is guided by the rear guide 24 provided in the discharge section 2, and its two ends in the width direction are guided by the side guides (not shown) provided in the discharge section 2. Thus, the decelerated sheet S stops at a predetermined position and is neatly stacked in the vertical direction on the tray P that is pre-set in the discharge section 2.

[0030] The appearance of vacuum suction wheel 3 is as follows Figure 2 As shown, and as Figure 3 As shown, the vacuum suction wheel 3 has an inner suction tube 31 and an outer suction tube 32. The inner suction tube 31 is configured such that its axial direction is orthogonal to the conveying direction of the sheet S in the discharge section 2, and the inner suction tube 31 is a straight tube fixed in the vacuum suction wheel 3. The outer suction tube 32 is located outside the diameter of the inner suction tube 31, is a straight tube covering the inner suction tube 31, and is configured to be rotatable relative to the inner suction tube 31 in the circumferential direction. The outer suction tube 32 is constructed as a straight tube and extends in the width direction of the sheet S, i.e., the conveying direction of the sheet S. The inner suction tube 31 functions as a support shaft that can rotatably support the outer suction tube 32. Both ends of the inner suction tube 31 are connected to a suction mechanism 4, which is part of the vacuum suction device. The suction mechanism 4 is provided at both ends of the vacuum suction wheel 3. The suction mechanism 4 is connected to a vacuum pump (not shown), and by driving the vacuum pump and through the suction mechanism 4, the internal space 31S of the inner suction tube 31 can be made negatively pressurized.

[0031] The inner suction tube 31 has a plurality of elongated holes 311…311 formed along the axial direction. Each elongated hole 311 penetrates the inner suction tube 31 radially. The inner suction tube 31 is fixed to the vacuum suction wheel 3 with the plurality of elongated holes 311…311 located on the upper side. Furthermore, the fixed position of the inner suction tube 31 in the vacuum suction wheel 3 can be changed in the circumferential direction. The axial formation position of the plurality of elongated holes 311…311 coincides with the formation position of the plurality of suction holes 323…323 formed in the outer suction tube 32. Thus, with the rotation of the outer suction tube 32, the plurality of suction holes 323…323 of the outer suction tube 32, which coincide with the plurality of elongated holes 311…311 of the inner suction tube 31, communicate with the internal space 31S of the inner suction tube 31, which is under negative pressure, thereby enabling the outer suction tube 32 to attract a single sheet of paper S.

[0032] The moving direction 21M of the paper feed clamp 21 (refer to) Figure 1 Compared to the moving speed on the tangential direction (horizontal direction in this embodiment), the suction outer tube 32 rotates at a low speed. In this embodiment, a gear 324 is provided at one end of the suction outer tube 32. On the other hand, the suction mechanism 4 is connected to a motor (not shown), and the driving force of the motor is transmitted to the suction outer tube 32 via the gear 324, thereby... Figure 1 When viewed from the axial direction, the suction outer tube 32 of the vacuum suction wheel 3 rotates counterclockwise.

[0033] like Figure 4 As shown, multiple planar portions 321...321 are provided at intervals along the circumference of the suction outer tube 32 on its outer periphery. In this embodiment, each planar portion 321 is provided at 20 locations. Figure 5 of (a), Figure 5 As shown in (b), on the outer periphery of the suction tube 32, planar portions 321 and circumferential portions 322 are alternately arranged in the circumferential direction of the suction tube 32. The planar portions 321 and circumferential portions 322 are arranged at equal angular intervals in the circumferential direction. The number and circumferential dimensions of each of the planar portions 321 and circumferential portions 322 can be suitably determined. The radius of the circumferential portions 322 is constant, that is, it is a curved surface 3221 with a constant curvature.

[0034] Each planar portion 321 has a plane 3211 orthogonal to the radial direction of the suction outer tube 32. The radial distance (radius) of this plane 3211 from its center is smaller than the portion (in this embodiment, the circumferential portion 322) sandwiched between two planar portions 321, 321 in the circumferential direction. In this embodiment, the formation range of each planar portion 321 and the plane 3211 is consistent, but as in the second embodiment described later, the formation range of each planar portion 321 (the groove-shaped portion) and the plane 3211 (the bottom surface of the groove-shaped portion) may not be consistent. In a radially cut cross-sectional shape, the plane 3211 is orthogonal to an imaginary line passing through the center of the suction outer tube 32. That is, the imaginary line coincides with the normal to the plane 3211. Furthermore, based on this plane 3211, the plane 3211 is formed with a uniform width in the circumferential direction. That is, the imaginary line passes through the center of the width direction of the plane 3211. In the radially cut cross-sectional shape, the radial distance from the center of the suction tube 32 to the plane 3211, i.e., the radius, except for the circumferential end edge, is smaller than the radius of the curved surface 3221 of the circumferential surface 322. Regarding the boundaries (circumferential end edges of each part) between the plane portion 321 and the circumferential surface 322, the parts 321 and 322 are connected in a manner with the same radius and no height difference. Furthermore, the boundaries can be formed into a gentle shape.

[0035] In each planar portion 321, the planar surface 3211 is continuously formed in the axial direction. By forming the planar surface 3211 in this way, the continuous planar surface 3211 (one planar surface 3211) in the axial direction uniformly abuts against the single sheet of paper S. That is, the planar portion 321 abuts against the single sheet of paper S with a planar surface. Therefore, compared with the existing structure in which the curved surface (suction tube) abuts against the planar surface (single sheet), air leakage is less likely to occur between each suction hole 323 and the surface or printing surface of the single sheet of paper S during suction, and the two can be tightly attached. Therefore, it is difficult to lose the suction force, and the single sheet of paper S can be effectively suctioned. Therefore, it is easy to decelerate the single sheet of paper S by suction, so the stacking of the single sheet of paper S will not be disordered, and stable paper discharge can be performed in the discharge section 2. In addition, it is possible to suppress the formation of scratches or dents on the edge of the single sheet of paper S due to the single sheet of paper S colliding with the front guide 23 with a strong head.

[0036] Here, when the outer circumferential surface of the material for the suction tube 32, i.e., the round tube, is chamfered to form the flat portion 321, for example, by cutting, the circumferential portion 322 is equivalent to the portion that has not been chamfered. In this way, the suction tube 32, in which the flat portion 321 and the circumferential portion 322 are alternately arranged, can be easily obtained by chamfering the round tube. Therefore, for example, the flat portion 321 can be formed by performing a normal processing, i.e., cutting, on the outer circumferential surface of the round tube. Furthermore, polishing the flat portion 321 and the circumferential portion 322 makes it less likely to snag on a single sheet of paper S.

[0037] In this embodiment, each planar portion 321 is longer in the axial direction than the maximum width dimension of a single sheet of paper S conveyed to the discharge section 2. Furthermore, as... Figure 2 As shown, in this embodiment, each planar portion 321 is provided along the entire length of the portion of the suction outer tube 32 exposed in the discharge section 2. Each planar portion 321 has a plurality of suction holes 323...323 that open outwards from the circumferential edge of the planar portion 3211. These plurality of suction holes 323...323 can communicate with the internal space 31S of the suction inner tube 31. Each suction hole 323 is circular in radial view and is a through hole that passes radially through the suction outer tube 32. However, the shape of each suction hole 323 is not limited to this. Moreover, in this embodiment, five suction holes 323 arranged axially are grouped together, and each group is arranged at a predetermined distance axially, but the arrangement of the suction holes 323 in the suction outer tube 32 is not particularly limited. However, in order to avoid forming unused suction holes 323, it is preferable to set the distance between the two ends of the plurality of suction holes 323...323 arranged axially to be smaller than the maximum width dimension of the single sheet of paper S conveyed to the discharge section 2.

[0038] As described above, the sheet of paper S, released from the paper discharge clamp 21 and moving in the discharge section 2 by inertia, is attracted by the plurality of suction holes 323...323 of the suction tube 32, thereby being held in the suction tube 32. As a result, the sheet of paper S is decelerated to the circumferential speed (more specifically, the tangential speed of the suction tube 32) of the rotating suction tube 32. In this embodiment, the suction tube 32 attracts the sheet of paper S at a position approximately centrally located near the rear (upstream) side of the transport direction (printing direction) of the sheet of paper S.

[0039] like Figure 5 As shown in (b), the suction hole 323 has an enlarged portion 3231, the diameter of which is enlarged at the outer diameter position. Furthermore, although not explicitly shown in the figure, the connection between the suction hole 323 (specifically the enlarged portion 3231) and the plane 3211 (opening edge, ridge portion) has a curved surface 3232 and is formed into a very small, smooth shape. Thus, the portion in contact with the sheet of paper S has no sharp corners (not sharp), but is formed into a smooth shape, so even when suction occurs and the suction tube 32 abuts against the sheet of paper S, it is difficult to damage the surface of the sheet of paper S or the printed surface formed on the sheet of paper S.

[0040] Next, the second embodiment will be described. Furthermore, the following description mainly focuses on aspects different from the first embodiment. In the second embodiment, as... Figures 6-8As shown, the planar portion 321 is a groove along the axial direction, and the plane 3211 of the planar portion 321 is formed at a deep position on the radially inner side. Therefore, unlike the first embodiment, the single sheet of paper S does not directly abut against the surface of each plane 3211, but abuts against the circumferential edge of each planar portion 321. However, even in this case, since the abutment state in the circumferential edge of each planar portion 321 is planar, the function of "attracting the single sheet of paper S through the plane" can be achieved, just like in the first embodiment.

[0041] Furthermore, in this second embodiment, since the flat portion 321 is grooved, the recessed flat portion 321 can be made into a uniform negative pressure. Therefore, compared with the first embodiment where only each suction hole 323 is made into a negative pressure, a larger area can be attracted for the single sheet of paper S. In addition, depending on the size of the single sheet of paper S, even if there is a portion in the flat portion 321 that does not overlap with the single sheet of paper S, an airflow will be generated that attracts the portion of the flat portion 321 that overlaps with the single sheet of paper S from that portion. The negative pressure generated by this airflow, combined with the direct attraction generated by the suction hole 323, creates an attraction between the portion of the flat portion 321 that overlaps with the single sheet of paper S and the single sheet of paper S.

[0042] Even in this second embodiment, compared to the existing structure where the curved surface (suction tube) abuts against the flat surface (sheet of paper), the sheet of paper S can be attracted more effectively. Therefore, the sheet of paper S can be easily decelerated, thereby enabling stable paper discharge in the discharge section 2.

[0043] The vacuum suction wheel 3 according to the two embodiments of the present invention has been described above. However, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

[0044] For example, instead of providing the circumferential surface 322, the two planar portions 321, 321 can be configured with different shapes. For example, the planar portions 3211 with suction holes 323 (the planar portions 321 in the above embodiment) can be formed with each other as planes without suction holes 323 (parts different from the planar portions 321 in the above embodiment).

[0045] Alternatively, for example, the suction tube 32 may be configured such that it is not configured as a straight tube extending in a direction orthogonal to the conveying direction of the sheet S, but rather as multiple straight tubes arranged in a row in a direction orthogonal to the conveying direction of the sheet S.

[0046] Explanation of reference numerals in the attached figures

[0047] 1: Sheet-fed printing press; 2: Discharge section; 3: Vacuum suction wheel; 4: Suction mechanism; 21: Paper discharge clamp; 21M: Moving direction of the paper discharge clamp; 22: Paper discharge chain; 23: Front guide; 24: Rear guide; 31: Suction inner tube; 31S: Internal space; 32: Suction outer tube; 311: Elongated hole; 321: Flat part; 322: Circumferential part; 323: Suction hole; 324: Gear; 3211: Flat surface; 3221: Curved surface (circumferential part); 3231: Enlarged part; 3232: Curved surface (suction hole); P: Pallet; S: Sheet-shaped material, sheet of paper.

Claims

1. A vacuum suction wheel, disposed in the discharge section of a sheet-fed printing press, wherein the vacuum suction wheel rotates while simultaneously attracting the sheet material on its outer periphery, thereby reducing the conveying speed of the sheet material, characterized in that... The vacuum suction wheel has an inner suction tube and an outer suction tube. The inner suction tube is a straight tube whose axial direction is orthogonal to the conveying direction and is fixed in the discharge section, and is capable of creating a negative pressure in its internal space. The outer suction tube is a straight tube located outside the diameter of the inner suction tube and is capable of rotating circumferentially relative to the inner suction tube. On the outer periphery of the suction tube, a plurality of planar portions are provided at intervals in the circumferential direction. The plurality of planar portions each have a plane orthogonal to the radial direction, which abuts against the single sheet material during attraction. The radius of this plane is smaller than the portion clamped by the planar portions in the circumferential direction. The plurality of planar portions each have a plurality of suction holes that open in a manner that does not connect with the circumferential edge of the planar portion, and the plurality of suction holes are capable of communicating with the internal space of the suction inner tube.

2. The vacuum suction wheel according to claim 1, characterized in that, The plane is formed continuously in the axial direction.

3. The vacuum suction wheel according to claim 1 or 2, characterized in that, In the outer periphery of the suction tube, the planar portion and the circumferential portion are alternately arranged in the circumferential direction. The circumferential surface has a curved surface with a constant radius.

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