Patent Application
20070126177
1. Field of the Invention
The present invention relates generally to sheet reversing mechanism of sheet-fed printing press, or more precisely, to de-coupling device of the reversing construction.
2. Description of the Prior Art
In sheet-fed printing press technique, there are one side printing in which only one surface of sheet is printed and two sides or perfecting printing in which both the front and back surfaces of sheet are printed. In order to switch printing mode, reversing cylinder with mechanism for sheet reversing is disposed between printing units. The reversing cylinder which plays the leading role in sheet reversing movement must be regulated in its phase in accordance with printing mode and sheet length. In concrete, cylinder drive gears of up- and down streams of the reversing cylinder must be mutually regulated in their rotational phases.
Therefore, a fixed gear and a regulating gear are provided in parallel to the end of shaft of reversing cylinder. Each gear is meshed with cylinder drive gears of up- and down streams. Unification of regulating gear must be temporally released for phase adjustment and then the regulating gear is coupled again.
Japanese patent laid-open No. 237161/1987 discloses de-coupling structure in which pressure disc urged by plate spring couples regulating gear with fixed gear of reversing cylinder and such coupling is released by pressure lever based upon lever principle.
But, the device can only be manually operated, not automated.
By Japanese patent No. 2924991, regulating gear is coupled by movable pressure rod which is co-axial with cylinder shaft, plate spring supported by the pressure rod and pressure lever urged by the plate spring.
For de-coupling, an adjusting cylinder actuated by pressure medium is disposed on one end of pressure rod and the rod is moved in the direction of cylinder shaft.
But, such pressure medium method has problems in sealing and difficulty in manufacturing, therefore, results in high cost.
In view of above-described problems of prior art technique, the present invention aims at fully automated de-coupling device with simple construction, smooth switching operation and durability.
To achieve these objects, de-coupling device according to the present invention comprises a shifting member by a pair of screw bolt and nut in co-axial relation with cylinder shaft. One end of the screw bolt is regularly engaged with power source and the other end can be pressed onto pressure lever in opposition to a plate spring. The screw nut is pivotally attached via radial bearing to flange member which is fixed to the end of the cylinder shaft and flange portion of nut abuts against the flange member via thrust bearing.
According to the present invention, de-coupling force can mechanically be transmitted in regularly engaging state, therefore, clutch means is not necessary and the device can be simplified, resulting in low cost and eliminating troubles. Inner opposition force due to de-coupling operation can be cancelled and excess force on bearing of shaft is prevented. Moreover, adjustment operation is smooth and mechanical durability is improved.
The above and other objects of the invention will become apparent from the following description of preferred embodiment taken in conjunction with the accompanying drawings. However, the following description is only an embodiment of the invention and the present invention is not limited to the embodiment.
An embodiment of de-coupling device according to the present invention is detailed here-in-under with reference to the drawings.
Flange member 22 has radial groove-like rooms 30 between the mounting ring 16 and a plurality of pressure levers 30 by lever principle are disposed in the room 30. As shown, one end of the pressure lever 32 near to the shaft center abuts against the plate springs 28 and screw bolt 36 of shifting member 34 comes in contact with the end. Other end of the lever 32 extending in radial direction has a projection 38 for lever action as well as contact portion 40 for uniting the regulating gear 20 with the mounting ring 16 and reversing cylinder.
Screw bolt 36 can be moved in compliance with the center of cylinder shaft 10 and rotation-free disc portion 42 at its tip end comes in contact with the pressure lever 32. Center portion of the screw bolt 36 engages with screw nut 44 as a pair of shift member 34. Pinion gear 46 is attached to the outer end of the screw bolt 36 and, as shown in
Next, de-coupling process by above-described construction is detailed. Power source 48 by air cylinder is actuated after stopping printing press as well as reversing cylinder. Then, the rack 50 is slid to rotate pinion gear 46 and screw bolt 36. The screw bolt 36 which engages with the screw nut 44 moves forward in the axial direction. Then, rotation-free disc portion 42 comes in contact with one end of pressure lever 32 so as to compress plate springs 28 in the opposite direction. On account of compressing plate springs 28, pressing by pressure lever 32 to regulating gear 20 is cancelled and, in this state, reversing cylinder (namely, the fixed gear 18 which is united with the reversing cylinder) is rotated up to the necessitated phase in order to alter relative rotational phase between the regulating gear 20.
After altering mutual rotational phase, screw bolt 36 is reversed by power source 48. Then, the screw bolt 36 moves backward and disc portion 42 parts from pressure lever 32. Thereby, urging by plate spring 28 onto the pressure lever 32 is restored and the regulating gear 20 is coupled again with the fixed gear 18 by the pressure lever 32.
Naturally, inner opposition force arises when compressing the plate springs 28 by screw bolt 36. But, such opposition force is consequently cancelled in the course of screw bolt 36, screw nut 44, thrust bearing 56 and finally, flange member 22 which is united with cylinder shaft 10. Screw nut 44 stands regularly still despite the rotation of reversing cylinder, as radial bearing 54 is interposed between the flange member 22. Moreover, screw bolt 36 is constantly in mesh with up to the power source 48.
The present invention is not limited to the embodiment described above; it can be extended and modified variously.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2005-353071 | Dec 2005 | JP | national |
