Offset press mechanism of offset press (3)

4 convex sleeve or eccentric sleeve pushing mechanism

When talking about the working principle of the squeezing and pressing mechanism, it all refers to the movement of the connecting rod to push the convex sleeve or the eccentric sleeve. Then where does the power of the connecting rod come from? The driving force of the connecting rod is indirectly from the clutching pressure cam, as shown in the figure. 2.9 shows.

1 is the pressure cam, 2 is the pressure cam, 3 is the connecting rod, 4 is the active rod, 5 is the supporting teeth, 6 is not bolstered, 7 is the connecting rod, 8 is the pendulum rod, 9 is the electromagnet, 10 is from Pendulum rod, 11 for the pressure swing rod.

When the pressure is applied, the connecting rod 7 pushes the supporter 5 upwards to contact with the support pad 6, the press cam pushes the pendulum 11 to swing, and at the same time, the support 5 and the active rod 4 are oscillated together, thereby driving the rod 3 to move downwards to achieve a combined pressure. When the pressure is released, the electromagnet releases the pendulum 8 and lifts it. Then, the bracing 5 comes out of contact with the bracing pad 6 on the pressure swing rod 11, and comes into contact with the bracing pad on the pressure swing rod 10. The pressure cam 2 pushes the swing lever 10 to swing, so that the support 5 and the active lever 4 swing together, so as to drive the linkage 3 to move upwards to achieve pressure release.

The clutch and pressure mechanism only allows the existence of two states: one is the combined pressure state and the Other is the pressure-releasing state, and the ambiguous state where the pressure does not exist and does not leave is not filled.

The sequence of sequential clutch pressures cannot be changed. The first high point of the press cam pushes the blanket cylinder and the printing cylinder together. The second point pushes the blanket cylinder and the impression cylinder together. The first high point of the pressure cam pushes the eraser. The cylinder and the impression cylinder are separated from each other, and the second point pushes the blanket cylinder and the plate cylinder away from each other. Since the squeegee and plate cylinders have different pressures from the platen, the latter is slightly larger, so the profile curves of the pressure cam and the pressure cam are also different.

5. Pressure regulating mechanism

The role of the pressure regulating mechanism is to change the center distance of the drum, that is, the center distance between the blanket cylinder and the plate cylinder, and the center distance between the blanket cylinder and the impression cylinder. The actions of the pressure regulating mechanism are carried out separately, ie each set of agencies is only responsible for adjusting the center distance of one place. Some pressure regulators have a set of machines, and some have two sets of machines; some machines have both sides tuned together, and some are individually tuned on both sides. A machine with a pressure regulating mechanism can only adjust the center distance between the blanket cylinder and the impression cylinder, and the center distance at the other can be adjusted. From the point of view of machine design, the meaning of having two pressure regulating mechanisms is not significant, because only the ink is transferred between the blanket cylinder and the plate cylinder. Generally, once adjusted, it can be adjusted for a long time. The pressure regulating mechanism between the blanket cylinder and the impression cylinder is a must, changing the gasket is troublesome, and moving the center distance is convenient.

The monotonous pressure regulating mechanism (that is, adjustment on one side and the pressure regulating mechanisms on both sides work at the same time), as long as the accuracy of the machine is ensured, the axis of the drum can always be kept parallel during pressure adjustment, but a drive shaft is required between the wall plates to hold both sides. Pressure regulators are linked together. The pressure regulating mechanisms that are adjusted on both sides individually, ie, the pressure regulating mechanisms on both sides, are individually adjusted and do not affect each other. Due to the existence of human factors, sometimes the two sides can not be adjusted exactly the same, which is very unfavorable to the work of the machine, so this structure has gradually begun to be eliminated on new machines. The pressure regulating mechanism is the same as the clutching pressure mechanism, and the center distance of the roller is also adjusted by changing the position of the convex sleeve or the eccentric sleeve. The axis line of the impression cylinder in the three cylinders is not moving, so only the blanket cylinder and the plate cylinder can be adjusted. The change of the axial position of the plate cylinder only affects the center distance between the cylinder and the blanket cylinder. The change of the position of the blanket cylinder may affect the center distance of the two cylinders. Therefore, when designing, it is always thought of that the adjustment of the center distance between the blanket cylinder and the impression cylinder has the least influence on the other center distance or has no effect. . The limit device installed on the pressure regulating mechanism determines the maximum amplitude of movement of the convex sleeve or the eccentric sleeve. Once outside this range, the mutual influence between the two center distances will increase significantly.

6. Differences and relations between pressure regulating agencies and clutch agencies

Both the pressure regulating mechanism and the clutching pressure mechanism essentially change the center distance of the drum. The way to change the center distance is to change the position of the convex sleeve or the eccentric sleeve. This is their common ground. Their similarities and differences are shown in:

1 The amount of change in the center distance is not the same The amount of change in the center distance caused by the pressure regulation is small compared to the amount of change in the center distance caused by the clutch pressure.
2 The pressure adjustment just changes the center distance of one place, and the center distance of the clutch pressure is changing.

3 There are only two distinct positions of the clutch pressure, either pressure or pressure, while the pressure regulation changes continuously within a range.

4 The clutch and pressure mechanism can work only when the machine is running, and it can be automatically performed. The pressure regulating mechanism can be adjusted when the machine is running or at rest, but it can only be manually operated, but the adjustment during exercise is better.

5 The clutch pressure mechanism is more complicated, and the pressure adjustment mechanism is relatively simple.

7. Limit device of clutch and pressure mechanism

The limit device of the clutch pressure mechanism is an important device for ensuring that the clutch pressure mechanism always works within the effective range. Without this device, when the pressure is combined, the inertia of the mechanism may exceed the maximum pressure-compressing position. When the pressure is released, the inertia of the mechanism may cause the maximum pressure-releasing position. When the speed is too high, the limit device may cause the rebound of the release pressure mechanism, resulting in that the release pressure mechanism cannot reach. How to eliminate the inertia of the clutch pressure mechanism has become a problem that must be considered in the design center. At present, some devices use friction braking devices. In this way, the speed of the clutch pressure mechanism can be reduced to zero when it reaches the maximum position, so that no shock is generated and there is no rebound phenomenon. The use of friction braking devices does not require the installation of limit devices. In fact, some manufacturers have begun to do so. Both the clutch pressure mechanism and the pressure regulating mechanism cause a change in the center distance, and therefore the mutual influence between them must be eliminated as much as possible. In other words, no matter how much the pressure adjustment, the two working conditions of the pressure-releasing mechanism should not be changed. This means that when the pressure regulator is required, the connecting rod can only swing with the pull point of the active lever as a fulcrum, and this condition must be met when designing. The stopper of the closing pressure mechanism must be installed correctly, that is, when the maximum clutch pressure is set, the distance between the active lever and the stopper is 0.1 mm. If it is too big, it will not reach the limit. If it is too small, it may make the clutching mechanism not in place.