JPH0825614A - Plate holder for printing press - Google Patents

Abstract

PURPOSE:To eliminate curving work of a second end part of a plate, make a rotational angle of a lever constant even when a plate cylinder is not stopped at a predetermined rotational position correctly for holding the end part, and moves a second holding mechanism to a predetermined holding position. CONSTITUTION:A second plate lockup device of a plate holding device is movable between a holding position adjacent to a wall face of an attaching groove for holding a second end part of a loosed plate and a tensile position separated from the wall face for tensioning the plate being held. A lever 52 which rotates with center at an axis 49 in parallel with an axial line L of a plate cylinder 7 is provided at a side plate 37. An air cylinder 55 separates from the lever 52 when the plate lockup device is to be moved to the tensile position and protrudes up to a stroke end when the lockup device is to be moved to the holding position so as to press and rotate the lever 52. A face 54a butting against a piston rod 56 in the lever 52 is formed into a circular arc so as to compose a part of a circle 58 with center at the axial line L when the lever 52 is rotated by the air cylinder 55.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate gripping device for gripping both ends of a plate in a printing machine such as an offset printing machine when the plate is mounted on a plate cylinder.

[0002]

2. Description of the Related Art As shown in FIG. 10, in a general offset printing machine 200, ink from an ink roller group 201 and water from a water roller group 202 are kneaded,
It is applied to the plate 204 held by the plate cylinder 203. Edition 20
After being transferred to the blanket 206 held by the blanket cylinder 205, the ink on the No. 4 is printed on the printing paper Pa on the circumferential surface of the impression cylinder 207. Thus, the state of the plate 204 is printed on the printing paper Pa by transferring twice. Therefore, the quality of the mounted state of the plate 204 on the plate cylinder 203 affects the print quality.

As shown in FIG. 11, a mounting groove 208 is formed on the outer periphery of the plate cylinder 203, and a first plate vise 211 is formed therein.
And a second plate vise 212 is attached. Edition 204
Is formed by a thin plate made of aluminum alloy.
The end portion 204a and the second end portion 204b are bent in advance by a dedicated processing machine. Plate cylinder 20 of plate 204
At the time of mounting to 3, the first end 204a is gripped by the first plate vise 211. In this state, the plate 204 is wrapped around the plate cylinder 203, and the second end 204b is gripped by the second plate vise 212 (prior art 1).

In the printing machine 200 described above, the plate 204
Not only is it time-consuming to bend both end portions 204a and 204b, but a dedicated bending machine is required, and there is a problem that the printing cost becomes high. Therefore, for example, Japanese Patent Laid-Open No. 6-
Japanese Patent No. 134972 discloses a plate gripping device that does not require bending of the second end portion 204b (prior art 2).

The second plate vise 21 in this plate gripping device
2 is movable between a grip position and a tension position in the mounting groove 208 as shown in FIG. The gripping position is a position where the plate vise 212 contacts the wall surface 208b of the mounting groove 208 in order to grip the second end portion 204b of the plate 204 in a loose state. As shown by the solid line in FIG. 12, the tension position is set by the plate vise 212 in order to tension the gripped plate 204.
Is a position away from the wall surface 208b.

Due to the movement between the two positions, a plate vise 2
12 is constantly urged toward the tension position by a coil spring 225. The drive shaft 226 between the plate vices 211 and 212 is rotatably supported by the side plate 215 of the plate cylinder 203. Pinion 228 on the outer periphery of the drive shaft 226
And the rack 229 of the plate vise 212 mesh with each other.

As shown in FIGS. 13 and 14, teeth 231 are formed on the outer periphery of a support shaft 227 that rotates integrally with the drive shaft 226. A lever 232 having teeth 233 and rotating about an axis 234 parallel to the axis L of the plate cylinder 203 is attached to the side plate 215. Teeth 231,2
33 are meshed with each other.

A lever drive mechanism 235 for rotating the lever 232 is provided near the side plate 215. The drive mechanism 235 includes a drive arm 236 that moves forward or backward in the radial direction of the plate cylinder 203 to contact or separate from the lever 232, and an air cylinder 2 that causes the piston rod 237 to move in and out of the cylinder 238 by compressed air.
39 and an intermediate component (lever, shaft, etc.) 24 interposed between the drive arm 236 and the air cylinder 239 and transmitting the movement of the piston rod 237 to the drive arm 236.
1 and 1.

When gripping the second end portion 204b, the plate cylinder 203 is rotated to a position where the lever 232 and the drive arm 236 face each other. The piston rod 237 is projected from the cylinder 238, and the drive arm 236 is advanced to the position shown by the chain double-dashed line in FIG. The lever 232 is pressed by this forward movement, and is rotated about the shaft 234, and the support shaft 227 is rotated in the opposite direction. The drive shaft 226 coaxial with the support shaft 227 rotates in the same direction, and the rotation is transmitted to the plate vise 212 via the pinion 228 and the rack 229, and the plate vise 212 is rotated by the coil spring 225.
Move against the urging force of. And piston rod 2
While 37 is protruding from the cylinder 238, that is,
Stroke end (Piston rod 237 is cylinder 2
38, the plate vise 212 is attached to the wall surface 20 of the mounting groove 208 at a timing before reaching the position (most protruding position 38).
It comes into contact with 8b and is held at the gripping position.

When the plate 204 is tensioned, the piston rod 237 is retracted into the cylinder 238 and the drive arm 23
6 retreats to the position shown by the solid line in FIG. Then, the drive arm 236 separates from the lever 232.
There is no force to press 32, and there is no force to hold plate vise 212 in the gripping position. Therefore, the plate vise 212 is automatically returned from the gripping position to the tensioned position by the biasing force of the coil spring 225. Along with this, the drive shaft 226 rotates, and the lever 232 is returned to the position shown by the solid line in FIG.

As described above, in the prior art 2, the second end 2
When grasping 04b, the plate vise 212 is once moved to the grasping position and the loose plate 204 is grasped. After the gripping, the plate vise 212 is moved to the tension position to tension the plate 204. Therefore, it is not necessary to bend the second end portion 204b for mounting the plate 204.

[0012]

In the prior art 2, when the plate vise 212 is moved to the gripping position, the plate vise 212 is moved at a timing before the piston rod 237 of the air cylinder 239 reaches the stroke end. Power 212
Contacts the wall surface 208b. At this time, piston rod 2
The force to project from the cylinder 238 remains in 37. This force is redundant to various components that constitute the force transmission path, such as the above-described intermediate component (lever, shaft, etc.) 241, drive arm 236, lever 232, support shaft 227, drive shaft 226, pinion 228, rack 229, and the like. Add as a heavy load. To solve this problem, the plate vise 212 is set to a grip position at a position slightly apart from the wall surface 208b, and the plate vise 212 reaches this grip position when the piston rod 237 projects to the stroke end. Is desirable.

However, in this way, the amount of protrusion of the piston rod 237 from the cylinder 238 is always constant. Therefore, when gripping the second end portion 204b, the plate cylinder 203 has a predetermined rotation phase (lever 232).
And the drive arm 236 do not stop accurately in the opposite rotation phase), the lever 23
The contact position of the second drive arm 236 is different. Along with this, the respective turning angles of the lever 232, the support shaft 227, the drive shaft 226, etc. are different, and the plate vise 212 is moved to a position deviated from the gripping position. as a result,
The amount of the second end portion 204b gripped by the plate vise 212 may change, the plate 204 may not be properly mounted on the plate cylinder 203, and the print quality may deteriorate.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to mount a plate on a plate cylinder without bending the second end and to grip a second plate vise. An excessive load is suppressed from being applied to various components that form the force transmission path for moving to the position, and the plate cylinder is not accurately stopped at a predetermined rotation phase because the second end is gripped. Even in such a case, it is an object of the present invention to provide a plate gripping device in a printing machine, which can always keep the rotation angle of the lever constant and move the second plate vise to a predetermined gripping position.

[0015]

To achieve the above object, a first invention according to claim 1 is a plate cylinder which rotates about an axis and has a mounting groove in a part of an outer periphery thereof, A first gripping mechanism provided in the mounting groove for gripping the first end of the plate, and the first end is gripped by the first gripping mechanism and wound around the outer periphery of the plate cylinder. A mechanism for gripping the second end of the plate in the attached state in the mounting groove, the mechanism being provided near the wall surface of the mounting groove facing the first gripping mechanism, A second gripping mechanism provided so as to be movable between a gripping position close to the wall surface for gripping the second end and a tensioning position separated from the wall surface for tensioning the gripped plate; An urging means for urging the second gripping mechanism to the tension position side, and rotation about an axis parallel to the axis of the plate cylinder. When moving the bar and the second gripping mechanism to the tension position, the bar and the second gripping mechanism are separated from the lever, and when the gripping mechanism is moved to the gripping position, the bar is pushed and rotated by stopping after moving to a predetermined position. A lever drive mechanism is provided, and when the second end portion is gripped, the rotation of the lever by the lever drive mechanism is transmitted to the second gripping mechanism, and the second force is exerted against the biasing force of the biasing means.
And a moving means for moving the gripping mechanism to a gripping position, the plate gripping device in a printing machine, wherein when the lever is rotated by the lever driving mechanism, a contact surface of the lever with the lever driving mechanism is The contact surface is formed in an arc shape so as to form a part of a circle centered on the axis of the plate cylinder.

According to a second aspect of the present invention, in addition to the structure of the first aspect, the lever drive mechanism is provided in the vicinity of the plate cylinder, and when the second gripping mechanism is moved to the gripping position, the lever driving mechanism is provided. It is provided with a rod that projects toward the axis of the plate cylinder and presses the lever.

[0017]

When the plate of the first aspect is mounted on the plate cylinder, the first end of the plate is gripped by the first gripping mechanism in the mounting groove. The plate is wrapped around the outer periphery of the plate cylinder and the second end of the plate is gripped by the second gripping mechanism in the mounting groove. During this gripping, the second gripping mechanism moves between the gripping position and the tensioned position. The gripping position is a position close to the wall surface to grip the second end of the plate in the loose state, and the tension position is a position away from the wall surface to tension the gripped plate. Due to the movement between the two positions, the movement means operates as follows.

When moving the second gripping mechanism to the gripping position, the lever driving mechanism of the moving means stops after moving to the predetermined position. This movement causes the lever to be pressed and rotated. The rotation is transmitted to the second gripping mechanism, and the second gripping mechanism moves to the gripping position against the biasing force of the biasing means. At this time, the lever drive mechanism is stopped at a predetermined position, and the second gripping mechanism is stopped slightly away from the wall surface of the mounting groove. The lever driving mechanism does not apply a force to the lever to rotate it by further pressing it. For this reason, it is difficult for an excessive load to be applied from the lever drive mechanism to various components that form the force transmission path for moving the gripping mechanism to the gripping position.

On the other hand, when the second gripping mechanism is moved to the tensioned position, the lever driving mechanism separates from the lever. The pressing force is not applied to the lever by the driving mechanism, and the force for moving the lever to the holding position side is not transmitted to the second holding mechanism. Therefore, the second gripping mechanism is moved to the tension position by the biasing force of the biasing means.

As described above, when mounting the plate on the plate cylinder,
The second end is gripped by the second gripping mechanism in the gripping position with the plate loosened. After gripping, the second gripping mechanism is moved to the tensioning position to tension the plate. Therefore, it is possible to mount the plate on the plate cylinder without bending the second end.

By the way, the gripping position of the second gripping mechanism is
It depends on the rotation angle of the lever by the lever drive mechanism. That is, the second gripping mechanism is moved to a predetermined gripping position only when the lever is rotated by a predetermined angle, and is moved to a position displaced from the gripping position when rotated by an angle different from the predetermined angle. Be moved.

Here, it is assumed that the shape of the lever is not devised so that the rotation angle of the lever is always a predetermined amount, and the pressing position of the lever by the lever drive mechanism is always constant. Then, the plate cylinder is not accurately stopped at a predetermined rotation phase, and if the contact surface of the lever with the lever drive mechanism is different for each stop position of the plate cylinder, the rotation angle of the lever is changed accordingly. . As a result, the second gripping mechanism is moved to a position displaced from the predetermined gripping position.

On the other hand, in the first invention, when the lever is rotated by the lever drive mechanism, the contact surface of the lever with the lever drive mechanism constitutes a part of a circle centered on the axis of the plate cylinder. Therefore, the contact surface is formed in an arc shape. Therefore, even if the plate cylinder is not accurately stopped at a predetermined rotation phase as described above and the contact surface of the lever with the lever drive mechanism is different for each stop position of the plate cylinder, the rotation angle of the lever Is constant. Therefore, the second gripping mechanism is always moved to a fixed gripping position.

In the second aspect of the invention, when the second gripping mechanism is moved to the gripping position, the rod of the lever drive mechanism is projected toward the axis of the plate cylinder. When the protruding rod contacts the lever, the lever is pressed and rotated. At this time, a force is applied from the rod to the lever only in the axial direction, and no force is applied in any other direction, for example, the tangential direction of the lever (the tangential direction of a circle around the axis of the plate cylinder). Therefore, the force is most efficiently transmitted from the rod to the lever.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the first and second inventions are embodied as a plate holding device in an offset printing machine for three-color printing will be described below with reference to FIGS.

As shown in FIG. 2, an offset printing machine (hereinafter, simply referred to as a printing machine) 1 includes a first printing unit 2,
It has a second printing unit 3 and a third printing unit 4. A feeder 5 is arranged near the first printing unit 2 on the paper feed side (left side in FIG. 2) of the printing machine 1, and near the third printing unit 4 on the paper discharge side (right side in FIG. 2). Then, the delivery device 6 is arranged.

A substantially cylindrical plate cylinder 7 is provided in each of the printing units 2 to 4 so as to be rotatable in the direction of arrow A. A thin plate-shaped plate (see FIG. 3) 8 made of an aluminum alloy is detachably attached to the outer periphery of the plate cylinder 7. Each plate cylinder 7
Ink is sent to the ink via the ink roller group 9 and water is sent via the water roller group 11. These ink and water are kneaded on the plate 8 on the outer periphery of each plate cylinder 7. The ink remaining as a print pattern on each plate 8 is transferred to a blanket (not shown) held on the blanket cylinder 12.

Then, the printing paper Pa is conveyed from the feeder 5 through the transfer cylinder 13 to the first printing unit 2. The printing paper Pa is held on the outer peripheral surface of the impression cylinder 14 and contacts the blanket on the blanket cylinder 12. At this time, the first color is printed on the printing paper Pa by the ink on the blanket. The blank cylinder 12 also rotates as the impression cylinder 14 rotates, and printing is performed on the entire printing paper Pa. Printing paper Pa
Is sent to the impression cylinder 14 of the second printing unit 3 via the transfer cylinder 15.

In the second printing unit 3, as in the first printing unit 2, the printing paper Pa is held on the outer peripheral surface of the impression cylinder 14 and comes into contact with the blanket on the blanket cylinder 12. At this time, the printing paper Pa. The second color is printed on Pa.
Further, the printing paper Pa is sent to the third printing unit 4 and is printed with the third color. The printing paper Pb printed as described above is transferred to the delivery device 6 and printing is completed.

Next, the plate gripping device used to mount the plate 8 on the plate cylinder 7 in each of the printing units 2 to 4 will be described. In addition, each plate gripping device has a printing unit 2 to
Since each of the four printing units has the same configuration, only the plate gripping device of the first printing unit 2 will be described here.

As shown in FIGS. 3 and 7, a mounting groove 16 is provided on the outer periphery of the plate cylinder 7. The mounting groove 16 includes a pair of wall surfaces 16 a and 16 b extending along the axis L of the plate cylinder 7. In the vicinity of the wall surface 16a in the mounting groove 16, a first plate vise 17 as a first gripping mechanism is arranged for gripping the first end 8a of the plate 8. This edition vise 1
7 is attached to the bottom surface 16c of the mounting groove 16 by a bolt 33 so as to be rotatable in the arrow E direction.

Similarly, in the vicinity of the wall surface 16b in the mounting groove 16, a second plate vise 18 as a second gripping mechanism is provided. The plate vise 18 has the first end 8a gripped by the first plate vise 17 and the second end 8b of the plate 8 wound around the plate cylinder 7 and attached to the mounting groove 16. It is a mechanism for gripping inside. The plate vise 18 is separated from the wall surface 16b to hold the second end portion 8b of the plate 8 in a loosened state and to grip the plate 8 (see FIG. 9) close to the wall surface 16b. It can be moved to and from the tensioned position (see FIG. 7). The plate vise 18 can also move in the direction along the axis L.

The second plate vise 18 has a grip block 21.
And a movable grip plate 22 mounted on the grip block 21 so as to be openable and closable. A washer 23 having a bow-shaped cross section is engaged with the movable grip plate 22. Bolt 24
The washer 23 and the movable grip plate 22 are penetrated and screwed to the grip block 21.

A cam shaft 25 extending along the axis L is rotatably interposed between the grip block 21 and the movable grip plate 22. A flat cam surface 25 a is formed on the outer periphery of the cam shaft 25. As shown in FIG. 5, a tension coil spring 26 is arranged on the opposite side of the bolt 24 with the cam shaft 25 interposed therebetween, one end of which is locked by the movable grip plate 22 and the other end of which is engaged by the grip block 21. It has been stopped. The tension coil spring 26 constantly pulls the base end of the movable grip plate 22 toward the grip block 21 side.

The cam surface 25a of the camshaft 25
When a portion other than the above contacts the movable gripping plate 22, the tip of the movable gripping plate 22 is brought closer to the gripping block 21 against the tensile force of the tension coil spring 26, and the second end 8 is formed between the two.
It becomes possible to grip b. Further, when the cam surface 25a comes into contact with the movable grip plate 22 (see FIG. 8), the tip end thereof is separated from the grip block 21.

As shown in FIG. 7, the first plate vise 17, like the second plate vise 18, has a cam having a grip block 27, a movable grip plate 28, a washer 29, a bolt 31, and a cam surface 32a. It is composed of a shaft 32, a tension coil spring (not shown), and the like. In the plate vise 17, when a portion of the cam shaft 32 other than the cam surface 32a comes into contact with the movable grip plate 28, the first end 8a of the plate 8 is gripped between the tip of the movable grip plate 28 and the grip block 27. It Also, the cam surface 32a
When the movable gripping plate 28 comes into contact with the movable gripping plate 28, the first end 8a held by the tip of the movable gripping plate 28 and the gripping block 27 is opened.

As shown in FIGS. 4 and 8, the second plate vise 18
A spring accommodating hole 45 is provided in the grip block 21 in parallel with the bottom surface 16 c of the mounting groove 16, and a shaft 46 inserted therein penetrates the grip block 21. A coil spring 47 as a biasing means is interposed in a compressed state between the head portion 46a of the shaft 46 and the bottom portion of the spring accommodating hole 45. The coil spring 47 causes the head portion 46a to move to the wall surface 1
The grip block 21 is constantly urged toward the tension position by being pressed by 6b.

The first printing unit 2 has a coil spring 47.
There is provided a moving means for moving the second plate vise 18 to the gripping position against the biasing force of the plate, or for moving the plate vise 18 to the tension position by utilizing the biasing force. Explaining this moving means, as shown in FIGS. 3 and 4, a drive shaft 36 extending along the axis L is disposed between the plate vices 17 and 18 in the mounting groove 16. The slide bearings 3 are respectively attached to the side plates 37 and 38 at the left and right ends of the plate cylinder 7.
9, 41 are attached. A support shaft 42 is fixed to the left end of the drive shaft 36. And this support shaft 42
And the right end of the drive shaft 36 are the slide bearings 39, 4
1 are rotatably inserted.

As shown in FIGS. 3 and 7, the drive shaft 36
The leg pieces 43 are inserted into a plurality of places spaced apart from each other, and the leg pieces 43 are fixed by tightening with nuts 40. Each leg piece 43 extends outward in the radial direction around the drive shaft 36, and a roller 44 is supported at the tip thereof. These rollers 44 have a drive shaft 36 indicated by an arrow B.
When rotated in the direction, the grip block 21 of the plate vise 18 is pressed against the urging force of the coil spring 47 in a direction approaching the wall surface 16b.

As shown in FIGS. 1 and 4, a large number of teeth 48 are formed on the outer periphery of the end of the support shaft 42 protruding from the left side plate 37. A shaft 49 extending parallel to the axis L of the plate cylinder 7 is fixed by a bolt 51 near the support shaft 42 on the side plate 37, and a lever 52 is rotatably supported on the shaft 49. The lever 52 is formed with a plurality of teeth 53 that mesh with the teeth 48 and a striking portion 54 that extends outward in a substantially radial direction around the shaft 49.

Inside the first printing unit 2, the side plate 3
An air cylinder 55 serving as a lever driving mechanism is arranged near 7. The air cylinder 55 is the cylinder body 5.
5a and a piston rod 56 that is retracted from the cylinder body 55a by compressed air. When the piston rod 56 moves the plate vise 18 to the tensioned position, the piston rod 56 shown in FIG.
As shown by the solid line in FIG.

The piston rod 56 projects from the cylinder body 55a when the plate vise 18 is moved to the gripping position. This protrusion is stopped when the piston rod 56 reaches its stroke end (the point where the piston rod 56 protrudes most from the cylinder body 55a). Piston rod 56
Presses the hitting portion 54 and rotates the lever 52 to the position shown by the chain double-dashed line. With this rotation, the support shaft 42 rotates in the direction of arrow B, and the leg piece 43 shown by the broken line tilts to the position shown by the chain double-dashed line. As a result, the roller 4 on the leg piece 43
4, the plate vise 18 is pushed toward the wall surface 16b and moved to the gripping position against the biasing force of the coil spring 47.

In FIG. 3, on the right side of the plate cylinder 7 and its vicinity, a clamping mechanism 57 for rotating the cam shafts 32 and 25 respectively for gripping and releasing the plate 8 by the plate vices 17 and 18. Is provided. The first printing unit 2 is wound around the plate cylinder 7 and has the end portions 8a,
To move the plate 8 to the predetermined position by finely moving the plate vise 18 along the axis L when the plate 8 held by the plate vise 17 or 18 is displaced from the predetermined position. The adjusting device 60 is provided.

In addition to the above construction, in the present embodiment, as shown in FIG. 1, when the piston rod 56 projects from the cylinder body 55a to the stroke end and the lever 52 is rotated, the striking portion that abuts the piston rod 56. An abutting surface 54a of 54 is formed in an arc shape so as to form a part of a circle 58 centered on the axis L of the plate cylinder 7. Also,
The air cylinder 55 is arranged so that the piston rod 56 appears and disappears toward the axis L.

Next, the operation and effect of this embodiment having the above-mentioned structure will be described. FIG. 7 shows a plate cylinder 7 and a plate 8
Shows the state when is attached. 1st edition vise 1
In FIG. 7, the cam surface 32 a of the cam shaft 32 is in contact with the movable grip plate 28, and the gap between the tip of the grip plate 28 and the grip block 27 is open. And the first of edition 8
The end 8a of the is inserted between the grip block 27 and the movable grip plate 28.

On the other hand, in the second plate vise 18, the cam surface 25a of the cam shaft 25 is brought into contact with the movable grip plate 22, and the tip of the grip plate 22 and the grip block 21 are opened. . Further, as shown by the solid line in FIG. 1, the piston rod 56 is retracted into the cylinder body 55a, and the lever 5
It is separated from the second tapping portion 54. The pressing force by the piston rod 56 does not act on the tapping portion 54. Therefore, this pressing force is not transmitted to the second plate vise 18 via the lever 52, the support shaft 42, the drive shaft 36, the leg pieces 43, and the roller 44. That is, the plate vise 18 is attached to the mounting groove 1
The force of pushing 6 toward the wall surface 16b does not act. Therefore, the plate vise 18 is pushed out in a direction away from the wall surface 16b by the urging force of the coil spring 47, and is held in the tension position.

Next, as shown in FIG. 8, the cam shaft 32 of the first plate vise 17 is rotated by the operation of the clamp mechanism 57 of FIG. 3, and a portion different from the cam surface 32a is movably gripped. The plate 28 is abutted. By this contact, the movable grip plate 28 swings around the bolt 31 as a fulcrum, and the grip plate 28
The first end 8 of the plate 8 between the tip of the plate and the grip block 27.
a is gripped. The state of the second plate vise 18 is the same as the state of FIG. 7 described above.

As described above, the plate cylinder 7 is rotated in the direction of arrow A with the first end portion 8a being held by the first plate vise 17, and the plate 8 is rotated by the rotation of the plate cylinder 7 with the rotation. It is wrapped around.

Thereafter, as shown by the chain double-dashed line in FIG. 1, the piston rod 56 is projected from the cylinder body 55a to the stroke end, and the tapping portion 54 of the lever 52 is pressed by the piston rod 56. By this pressing, the lever 52 rotates in the direction of arrow D about the shaft 49, and the support shaft 42 meshing with the lever 52 moves in the opposite direction (direction of arrow B).
Is turned to. The drive shaft 36 rotates integrally with the support shaft 42, and the leg piece 43 and the roller 44 tilt from the position shown by the chain double-dashed line in FIG. 9 to the position shown by the solid line. Due to this tilting, the second plate vise 18 is pressed against the biasing force of the coil spring 47 and approaches the wall surface 16b of the mounting groove 16.

Second end 8 of plate 8 wrapped around plate cylinder 7.
b is inserted between the grip block 21 and the movable grip plate 22. The operation of the clamp mechanism 57 of FIG.
The cam shaft 25 of the plate vise 18 is rotated, and a portion different from the cam surface 25a is brought into contact with the movable grip plate 22. This contact causes the movable grip plate 22 to swing, and the second end 8b of the plate 8 is gripped between the tip of the grip plate 22 and the grip block 21.

Subsequently, as shown by the solid line in FIG. 1, the piston rod 56 is retracted into the cylinder body 55a, and the lever 5
It is separated from the second tapping portion 54. The pressing force of the piston rod 56 does not act on the tapping portion 54, and the plate vise 18
The force that pushes against the wall surface 16b of the mounting groove 16 does not act. Therefore, the plate vise 18 is pushed out by the biasing force of the coil spring 47 in the direction away from the wall surface 16b. Due to the movement of the plate vise 18, the plate 8 wound around the outer periphery of the plate cylinder 7 is tensioned (tensioned without looseness).

As described above, when the plate 8 is mounted on the plate cylinder 7, the second end 8b is gripped by the plate vise 18 at the gripping position while the plate 8 is loosened. After grasping, plate vise 18
Is moved to the tension position and the plate 8 is tensioned. Therefore, unlike the prior art 1, the plate 8 can be mounted on the plate cylinder 7 without bending the second end 8b. Along with this, a dedicated bending machine becomes unnecessary, and it is possible to suppress an increase in printing cost.

In the prior art 2, the second plate vise 21 is used.
When the piston 2 is moved to the gripping position, the plate vise 212 contacts the wall surface 208b at a timing before the piston rod 237 reaches the stroke end. At this time, the piston rod 237 still has a force to project from the cylinder 238. This force is generated by various components that form a force transmission path for moving the plate vise 212 to the gripping position.
For example, it is applied as an extra load to the intermediate parts (lever, shaft, etc.) 241 and the like.

On the other hand, in this embodiment, when the plate vise 18 is at a grip position at a position slightly separated from the wall surface 16b, and the piston rod 56 projects to the stroke end,
The plate vise 18 reaches this gripping position. Piston rod 56
Does not further project, so that no extra load is applied to various parts constituting the force transmission path from the piston rod 56 to the plate vise 18.

The gripping position of the plate vise 18 differs depending on the turning angle of the lever 52 by the piston rod 56. That is, the plate vise 18 is moved to a predetermined gripping position only when the lever 52 is rotated by a predetermined angle, and is moved to a position displaced from the gripping position when rotated by an angle different from the predetermined angle. To be done.

Here, it is assumed that the shape of the lever 52 is not devised so that the turning angle of the lever 52 is always a predetermined amount (corresponding to the prior art 2). At this time, since the piston rod 56 projects to the stroke end, the position of its tip is always constant. Then, the plate cylinder 7
Is not accurately stopped at a predetermined rotation phase, and the abutment surface 54a of the lever 52 with the piston rod 56 has its plate cylinder 7
The rotation angle of the lever 52 varies depending on the stop position. As a result, the plate vise 18 is moved to a position displaced from a predetermined gripping position.

On the other hand, in this embodiment, the air cylinder 5
When the lever 52 is rotated by 5, the contact surface 54a of the lever 52 with the piston rod 56 is
It is formed in an arc shape so as to form a part of a circle 58 centered on the axis L of. Therefore, as described above, the plate cylinder 7
Does not stop accurately in a predetermined rotation phase, and the piston rod 56 in the lever 52 is
Even if the contact surface 54a for contacting the plate differs depending on the stop position of the plate cylinder 7, the rotation angle of the lever 52 is constant. Therefore, the plate vise 18 can always be moved to a fixed gripping position.

In this embodiment, when the plate vise 18 is moved to the gripping position, the piston rod 56 moves the plate cylinder 7
Is projected toward the axis L of. When the protruding piston rod 56 contacts the lever 52, the lever 52 is pressed and rotated. At this time, a force is applied from the piston rod 56 to the lever 52 only in the direction of the axis L, and no force is applied in any other direction, for example, in the tangential direction of the lever 52 (the tangential direction of the circle 58 about the axis L). . Therefore, the force can be transmitted most efficiently from the piston rod 56 to the lever 52.

Further, in this embodiment, the cylinder body 55a is
The air cylinder 55 is provided with a piston rod 56 that moves in and out of the cylinder body 55a by compressed air. Then, when the plate vise 18 is moved to the gripping position, the piston rod 56 is projected to the stroke end and stopped. Therefore, the lever drive mechanism can be configured with a small number of parts and a simple mechanism, and the piston rod 56 can always be reliably stopped at a fixed position.

The present invention can be embodied in another embodiment shown below. (1) In the above-described embodiment, the lever 52 is directly rotated by the piston rod 56 of the air cylinder 55. Etc.) may be interposed.

(2) Air cylinder 5 in the above embodiment
The piston rod 56 of No. 5 may be retracted toward a position different from the axis L. (3) A hydraulic cylinder may be used instead of the air cylinder 55.

(4) The plate vise 18 may be moved directly by the leg pieces 43 without the roller 44 in the above embodiment. Further, instead of the leg piece 43, the roller 44, etc. of the above-mentioned embodiment, the rack and pinion as shown in the prior art 2 may be used. That is, the drive shaft 36
A pinion is formed on the outer periphery of the plate and the rack is fixed to the plate vise 18, and the pinion and the rack are meshed with each other. Then, the rotation of the drive shaft 36 is transmitted to the plate vise 18 via the pinion and the rack and moved to the gripping position.

(5) As a biasing means, a coil spring 47 is used.
Besides, various springs such as a leaf spring, a spiral spring, a rod spring, and a bamboo shoot spring can be used. Also synthetic rubber,
It is also possible to use a polymer elastic body such as natural rubber or elastic plastic, or a fluid utilizing elastic body such as an air cushion or a hydraulic cushion.

Although the respective embodiments of the present invention have been described above, technical ideas other than the claims which can be understood from the respective embodiments will be described below together with their effects. (A) In the plate gripping device according to claim 1, the lever driving mechanism includes a cylinder body and a piston rod that is retracted from the cylinder body by the pressure of fluid, and moves the second gripping mechanism to a gripping position. A plate gripping device in a printing press in which a piston rod reaches a stroke end and stops when moving.

By doing so, the lever drive mechanism can be configured with a small number of parts and a simple mechanism, and the piston rod can always be reliably stopped at a fixed position.

[0066]

As described in detail above, according to the first invention, the plate can be mounted on the plate cylinder without bending the second end. In addition, it is possible to prevent an extra load from being applied to various parts that constitute the force transmission path for moving the second gripping mechanism to the gripping position. Further, even when the plate cylinder is not accurately stopped at the predetermined rotation phase due to the gripping of the second end portion, the rotation angle of the lever is always kept constant and the second gripping mechanism is held at the predetermined gripping position. Can be moved to.

According to the second invention, in addition to the effect of the first invention, when the rod of the lever drive mechanism projects, the pressing force of the rod can be most efficiently transmitted to the lever.

[Brief description of drawings]

FIG. 1 shows a plate gripping device of an embodiment embodying the first and second inventions, showing a support shaft and a lever attached to a side plate of the plate cylinder, and an air cylinder arranged near the plate cylinder. It is a partially expanded side view.

FIG. 2 is a schematic configuration diagram of an offset printing machine.

FIG. 3 is a front view of a plate gripping device.

FIG. 4 is an enlarged front view showing a part of the plate gripping device in FIG. 3 in a cutaway manner.

5 is an enlarged cross-sectional view taken along line YY of FIG.

6 is a partially enlarged side view showing a state in which the piston rod of the air cylinder of FIG. 1 is projected to the stroke end to rotate the lever.

FIG. 7 is a partially enlarged side view showing a state before the first end of the plate is gripped by the first plate vise.

8 is a partially enlarged side view showing a state where the first end portion in FIG. 7 is gripped by a first plate vise.

9 is a partially enlarged side view showing a state in which the second end portion of the plate in FIG. 8 is gripped by a second plate vise.

FIG. 10 is a schematic configuration diagram showing the periphery of a plate cylinder in the offset printing machine of Prior Art 1.

FIG. 11 is a cross-sectional view showing a state in which a plate whose both ends are bent is mounted on a plate cylinder in Prior Art 1.

FIG. 12 is a second example of the prior art 2 due to the tension of the plate.
FIG. 6 is a partial front view showing a state in which the plate vise is moved to a tension position.

FIG. 13 shows a second example of the prior art 2 for gripping a plate.
FIG. 8 is a partial side view showing a state in which the plate vise of FIG.

FIG. 14 is a partial side view showing a support shaft and a lever attached to a side plate of a plate cylinder and a lever drive mechanism arranged in the vicinity of the plate cylinder in Conventional Technique 2.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Printing machine, 7 ... Plate cylinder, 8 ... Plate, 8a ... 1st edge part, 8
b ... 2nd end part, 16 ... mounting groove, 16b ... wall surface, 17 ...
First plate vise as first gripping mechanism, 18 ... Second plate vise as second gripping mechanism, 47 ... Coil spring as biasing means, 49 ... Shaft, 52 ... Lever, 54a ... Abutment surface, 55 ... Air cylinder as lever driving mechanism, 56
… Piston rod, 58… Circle, L… Axis of plate cylinder.

Claims (2)

[Claims] 1. A plate cylinder which rotates about an axis and has a mounting groove in a part of its outer periphery, and a first grip provided in the mounting groove for gripping a first end of the plate. And a mechanism for gripping the second end of the plate in a state where the first end is gripped by the first gripping mechanism and is wound around the outer periphery of the plate cylinder in the mounting groove. And a gripping position which is provided near the wall surface of the mounting groove facing the first gripping mechanism and is close to the wall surface for gripping the second end of the loose plate, and the gripped plate is tensioned. A second gripping mechanism provided so as to be able to move between a tensioned position spaced apart from the wall surface, a biasing means for biasing the second gripping mechanism toward the tensioned position, and an axis line of the plate cylinder. A lever that rotates about an axis parallel to the lever, and a lever when moving the second gripping mechanism to the tension position. And a lever driving mechanism for moving the gripping mechanism to a gripping position to move the gripping mechanism to a predetermined position and then stop the lever to press and rotate the lever. When gripping the second end, the lever driving mechanism is provided. A plate gripping device in a printing machine including: a moving unit that transmits the rotation of the lever by the driving mechanism to the second gripping mechanism and moves the second gripping mechanism to the gripping position against the biasing force of the biasing unit. When the lever is rotated by the lever drive mechanism, the contact surface of the lever with the lever drive mechanism forms a part of a circle around the axis of the plate cylinder. A plate gripping device in a printing machine in which the contact surface is formed in an arc shape. 2. The lever driving mechanism is provided in the vicinity of the plate cylinder, and includes a rod that projects toward the axis of the plate cylinder and presses the lever when moving the second gripping mechanism to the gripping position. A plate gripping device in the printing machine according to Item 1.