BACKGROUND OF THE INVENTION 0001 The present invention relates to a plate inserting apparatus for inserting a new plate in the plate clamp device of a plate cylinder. 0002 Japanese Patent Publication No. 7-75885 (reference 1) discloses a plate inserting apparatus of this type. The apparatus disclosed in reference 1 has a plate magazine supported to be movable between an inserting position for inserting a new plate into the plate clamp device of a plate cylinder and a wait position, a conveyor belt provided in the plate magazine to feed out the new plate into a plate fixing unit, and a driver for driving the conveyor belt. When the plate magazine is located at the inserting position, the conveyor belt is driven by the driver. As a driving belt travels, the new plate is fed out from the plate magazine into the plate clamp device of the plate cylinder, and is mounted on the plate cylinder. 0003 In the conventional plate inserting apparatus described above, since the new plate is fed out into a plate fixing device by the travel of the conveyor belt, the driver for driving the conveyor belt to travel is required. As the driver is large and heavy, a rotational driving unit for rotating the plate magazine also becomes large, and the entire apparatus becomes large and complicated.

SUMMARY OF THE INVENTION 0004 It is an object of the present invention to provide a compact plate inserting apparatus. 0005 It is another object of the present invention to provide a simplified plate inserting apparatus. 0006 In order to achieve the above objects, according to the present invention, there is provided a plate inserting apparatus comprising plate holding means for holding a plate to which an elastic restoration force is applied, and releasing means for releasing the plate held by the plate holding means, wherein the plate released by the releasing means is inserted into a plate fixing unit provided in a plate cylinder by the elastic restoration force thereof.

BRIEF DESCRIPTION OF THE DRAWINGS 0007 FIG. 1 is a view showing the arrangement of a sheet-fed rotary printing press to which a plate inserting apparatus according to the present invention is applied; 0008 FIG. 2A is a side view showing the structure of the plate cylinder shown in FIG. 1; 0009 FIG. 2B is a perspective view of a plate to be mounted on the outer surface of the plate cylinder of FIG. 2A; 0010 FIG. 3 is a side view of a plate inserting apparatus according to an embodiment of the present invention; 0011 FIGS. 4A and 4B are enlarged views of a portion IV of FIG. 3; 0012 FIG. 5 is a side view of the plate inserting apparatus which has prepared for supplying a new plate; 0013 FIG. 6 is a side view of the plate inserting apparatus in a state wherein a plate feed unit is close to the plate cylinder; 0014 FIG. 7 is a side view of the plate inserting apparatus in a state wherein a plate changing device releases a plate and a new plate is inserted into the leading edge plate clamp device of the plate cylinder; 0015 FIG. 8 is a side view of the plate inserting apparatus in a state wherein the new plate is mounted on the plate cylinder; and 0016 FIG. 9 is a side view of the plate inserting apparatus in a state wherein the plate feed unit is restored to the original position.

DESCRIPTION OF THE PREFERRED EMBODIMENT 0017 A plate inserting apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 to 9. As shown in FIG. 1, a sheet-fed rotary printing press 1 has a feeder 2 for feeding sheets, a plurality of printing units 3 corresponding to four different ink colors to print the sheets fed from the feeder 2 in the respective ink colors, and a delivery unit 4 where the sheets delivered from the last printing unit 3 are stacked. A plate cylinder 5 on which a plate is mounted and which is rotatably supported by frames is provided in each printing unit 3, and a safety cover 6 is provided on the delivery side of each printing unit 3. The safety cover 6 is moved up and down (in the vertical direction) by an air cylinder (not shown). When the safety cover 6 moves upward, it opens the front portion of the corresponding plate cylinder 5. When the safety cover 6 moves downward, it covers the front portion of the corresponding plate cylinder 5. 0018 A suction pump 51 is connected to the lower ends of the safety covers 6 to supply suction air to a plurality of suction pads for chucking the front ends of the corresponding plates. Solenoid valves (releasing means) 52 are connected between the suction pump 51 and the suction pads, and open/disconnect air flow channels by their opening/closing operations. The opening/closing operations of the solenoid valves 52 are controlled by a controller 53. 0019 As shown in FIG. 2A, the plate cylinder 5 has a notch 7 in its outer surface to extend in the axial direction. A leading edge plate clamp device 8 and trailing edge plate clamp device 9 are provided in the notch 7. As shown in FIG. 2B, a new plate 10 has a U-shaped positioning notch 11a and a positioning notch 11b with a semicircular bottom in its leading edge, and a bent portion 12 bent at a right angle in its trailing edge. As shown in FIG. 3, the safety cover 6 is comprised of three covers, i.e., upper, middle, and lower covers 6a, 6b, and 6c. The three covers 6a, 6b, and 6c are sequentially connected to each other, and are integrally moved by the air cylinder (not shown) vertically. 0020 The plate inserting apparatus will be described with reference to FIG. 3 and FIGS. 4A and 4B. As shown in FIG. 3, the upper cover 6a has a locking portion 15 with an inverted-L shape, when seen from the side surface, to lock the trailing edge of the new plate 10. A pair of rod-like guide bars 16 and 17 extend parallel to each other at a predetermined distance from the outer surface of the middle cover 6b, such that their axes extend in the widthwise direction of the middle cover 6b. The two ends of the guide bar 16 and those of the guide bar 17 are supported at the upper and lower portions of the middle cover 6b by support members 16a and 17b, respectively. 0021 A rectangular window 20 extending in the horizontal direction (the widthwise direction of the cover) is formed in the upper portion of the lower cover 6c. At positions corresponding to the lower end of the window 20, a pair of positioning pins 21 are fixed to the lower cover 6c through a support plate 22. Before mounting the new plate 10 onto the plate cylinder 5, its positioning notches 11a and 11b are engaged with the positioning pins 21, so that the lower end of the new plate 10 is supported by the positioning pins 21. 0022 Subsequently, after the upper and lower portions of the new plate 10 are supported by the pair of guide bars 16 and 17, the upper end of the new plate 10 is engaged in the locking portion 15 and locked by it. Thus, the new plate 10 elastically deforms in the widthwise direction between the pair of guide bars 16 and 17, and flexes largely. Then, the lower end of the new plate 10 is chucked by suction pads 27 of a plate feed unit 25, and the plate feed unit 25 is swung to come close to the plate cylinder 5. At this time, the new plate 10 keeps flexing between the pair of guide bars 16 and 17, as indicated by an alternate long and two short dashed line in FIG. 3. 0023 When the suction pads 27 release the new plate 10, the lower end (leading edge) of the new plate 10 is inserted in the leading edge plate clamp device 8 of the plate cylinder 5 by the elastic restoration force generated by the flex of the new plate 10. At this time, the pair of guide bars 16 and 17 guide the leading edge of the new plate 10 to insert it into the leading edge plate clamp device 8 of the plate cylinder 5. 0024 As shown in FIG. 4A, the plate feed unit 25 as a swing member is comprised of a swing plate 26 for selectively covering the window 20, the suction pads 27 for attracting the new plate 10, a first guide roller (first rotary member) 28 serving as a guide member when inserting the new plate 10 in the plate cylinder 5, and a pin 29 for swinging the swing plate 26. The swing plate 26 has an elongated rectangular shape with a size slightly smaller than that of the window 20, and a pair of opposing bars 30 (one bar 30 is not shown) are fixed to its two ends in the horizontal direction. The swing plate 26 has a plurality of holes 26a in its lower portion, through which the suction pads 27 are exposed. 0025 As the upper portions of the bars 30 are rotatably supported by a pivot shaft 32 standing from the lower cover 6c, the swing plate 26 is supported by the middle cover 6b to be swingable about the pivot shaft 32 as the pivot center. The suction pads 27 are fixed to the rear side of the swing plate 26 through a bracket (not shown), and suction air is supplied to it from the suction pump 51 through the corresponding solenoid valve 52. The pin 29 is fixed to the bars 30 through support plates (not shown), and projects from the sides of the plate feed unit 25. 0026 As shown in FIG. 4B, an air cylinder 35 for swinging the plate feed unit 25 is rotatably supported by an apparatus fixing portion through a small shaft 36 provided to its lower end. An engaging member 38 is attached to the distal end of a rod 37 of the air cylinder 35, and has a U-groove 38a, in its upper end, to engage with the pin 29. 0027 In this arrangement, when the rod 37 of the air cylinder 35 moves backward, the plate feed unit 25, in which the pin 29 engages with the U-groove 38a of the engaging member 38, covers the window 20, that is, the plate feed unit 25 is located at a wait position away from the plate cylinder 5. When the rod 37 of the air cylinder 35 moves forward as indicated by an alternate long and two short dashed line in FIG. 4B, the plate feed unit 25 pivots counterclockwise about the pivot shaft 32 as the pivot center through the pin 29 engaging with the U-groove 38a of the engaging member 38. Hence, the lower end of the plate feed unit 25 is positioned at the inserting position close to the plate cylinder 5. 0028 A second guide roller (second rotary member) 45 for guiding the leading edge of the new plate 10 to the plate cylinder 5, and press rollers 43 for inserting the trailing edge of the new plate 10 into the plate cylinder 5 will be described with reference to FIG. 3. A driving shaft 40 rotatably supported between the pair of frames (not shown) is pivoted by a lever and actuator (not shown). One end of each of a pair of opposing support arms 41 (one support arm 41 is not shown) is fixed to the corresponding one of the two ends of the driving shaft 40, and a shaft 42 extends horizontally between the other-end portions of the support arms 41. The plurality of press rollers 43 are formed on the shaft 42 to line up in the axial direction. One end of a support plate 44 is fixed to the shaft 42, and the other end of the support plate 44 rotatably, axially supports the second guide roller 45. 0029 In this arrangement, when the driving shaft 40 pivots clockwise in FIG. 3, the press rollers 43 come into contact opposite to the outer surface of the plate cylinder 5. Simultaneously, the second guide roller 45 moves in a direction to come close to the first guide roller 28, and clamps the distal end of the new plate 10 chucked by the suction pads 27 together with the first guide roller 28. When the air flow channel is disconnected by the solenoid valves 52, the new plate 10 chucked by the suction pads 27 is released. The released new plate 10 is clamped between the first and second first guide rollers 28 and 45 and guided to the leading edge plate clamp device 8 of the plate cylinder 5. Therefore, the leading edge of the new plate 10 is inserted into the leading edge plate clamp device 8 of the plate cylinder 5, and is gripped by it. 0030 The plate inserting operation of the plate inserting apparatus with the above arrangement will be described with reference to FIG. 4B and FIGS. 5 to 9. 0031 In the initial state, the upper, middle, and lower covers 6a, 6b, and 6c are located in the lower portion. Accordingly, the front portion of the plate cylinder 5 is covered by the middle and lower covers 6b and 6c. In this state, the notches 11a and 11b formed in the leading edge (lower portion in FIG. 5) of the new plate 10 engage with the positioning pins 21, so that the lower end of the new plate 10 is supported by the positioning pins 21. The new plate 10 is positioned temporarily by engagement of the notches 11a and 11b with the positioning pins 21, so that the mounting precision of the new plate 10 with respect to the plate cylinder 5 improves. 0032 Subsequently, the upper and lower portions of the new plate 10 are attached against the pair of guide bars 16 and 17, and the upper end of the new plate 10 is locked by the locking portion 15. Thus, the new plate 10 is supported by the safety cover 6. At this time, the new plate 10 supported by the safety cover 6 largely flexes between the pair of guide bars 16 and 17. Then, the solenoid valve 52 is opened by the control operation of the controller 53, and the lower end of the new plate 10 is chucked by the suction pads 27 of the plate feed unit 25. 0033 Subsequently, the rod 37 of the air cylinder 35 is moved forward, and accordingly the pin 29 engaging with the U-groove 38a of the engaging member 38 also moves to the position indicated by an alternate long and two short dashed line in FIG. 4B. As the pin 29 moves, the plate feed unit 25 pivots counterclockwise in FIG. 4B about the pivot shaft 32 as the pivot center. When the plate feed unit 25 pivots, the lower end of the plate feed unit 25 comes close to the plate cylinder 5, and the plate feed unit 25 is accordingly positioned at the inserting position. 0034 At this time, the notches 11a and 11b disengage from the positioning pins 21, and the front end of the new plate 10 is held only by the suction pads 27. With this arrangement, when the new plate 10 is to be moved to the inserting position, no actuator is needed for moving the positioning pins 21 (backward). 0035 Then, the driving shaft 40 (FIG. 3) pivots clockwise in FIG. 3, and the press rollers 43 come into contact opposite to the outer surface of the plate cylinder 5, as shown in FIG. 7. Simultaneously, the second guide roller 45 comes into contact opposite to the first guide roller 28 through the new plate 10. The solenoid valve 52 is then closed by the control operation of the controller 53, and an air flow channel to the suction pads 27 is disconnected. Hence, the new plate 10 chucked by the suction pads 27 is released, and the lower end (leading edge) of the new plate 10 is inserted into the leading edge plate clamp device 8 of the plate cylinder 5 by the elastic restoration force generated by the flex of the new plate 10. 0036 According to this embodiment, as the new plate 10 is inserted into the leading edge plate clamp device 8 of the plate cylinder 5 by its elastic restoration force, no member is required for moving the new plate 10, and the apparatus is made compact and simplified. As the new plate 10 can flex by its own weight, no driving source is required for inserting the leading edge of the new plate 10 into the leading edge plate clamp device 8 of the plate cylinder 5, and the number of components can be reduced largely. As the new plate 10 can be held and released by supplying and disconnecting the suction air, the structure is simplified. 0037 As the new plate 10 is guided to the leading edge plate clamp device 8 of the plate cylinder 5 by the first and second guide rollers 28 and 45, the leading edge of the new plate 10 can be inserted into the leading edge plate clamp device 8 reliably. When the plate feed unit 25 is located at the position of inserting the new plate 10, the pair of guide bars 16 and 17 guide the new plate 10 to the plate cylinder 5. Thus, the new plate 10 can be inserted into the leading edge plate clamp device 8 of the plate cylinder 5 reliably. The guide bars 16 and 17 support the new plate 10 when the plate feed unit 25 is at a position retreated from the plate cylinder 5. Hence, no exclusive support member is required, and the number of components and the manufacturing cost can be reduced. 0038 Subsequently, as shown in FIG. 8, when the plate cylinder 5 pivots counterclockwise, the new plate 10 is pressed by the press rollers 43 to come into tight contact with the outer surface of the plate cylinder 5. When the plate cylinder 5 rotates substantially by one turn, the bent portion 12 of the new plate 10 as the trailing edge is inserted into the trailing edge plate clamp device 9 of the plate cylinder 5 by the press rollers 43. Hence, the trailing edge of the new plate 10 is gripped by the trailing edge plate clamp device 9 of the plate cylinder 5, and the new plate 10 is mounted on the outer surface of the plate cylinder 5. 0039 Subsequently, as shown in FIG. 4B, the rod 37 of the air cylinder 35 is moved backward as indicated by a solid line, so that the pin 29 engaging in the U-groove 38a of the engaging member 38 also moves to the position indicated by a solid line. Thus, as shown in FIG. 9, the plate feed unit 25 pivots by its own weight clockwise in FIG. 9 about the pivot shaft 32 as the pivot center, and is positioned at a position retreated from the plate cylinder 5 to cover the window 20. 0040 As has been described above, according to the present invention, when inserting the plate into the leading edge plate clamp, a convey member for moving the plate and a driving means for driving the convey member become unnecessary. Thus, the apparatus is made compact and simplified.