Horizontal strip ghosting failure and mechanism de

Horizontal strip ghosting failure and mechanism design improvement of offset press II

1. Experimental results, experimental data and force displacement curve screen display 3 rubber drum clutch pressing shaft sleeve structure

the rubber drum clutch pressing shaft sleeve of most offset presses adopts two structures: one is eccentric sleeve structure (as shown in Figure 2a), the other is three-point support structure (as shown in Figure 2b). The eccentric shaft sleeve structure is used most

1) eccentric shaft sleeve under force

when pressing and printing, if the force acting on the eccentric shaft sleeve is along the eccentric direction of the eccentric shaft sleeve, the side eccentric shaft sleeve has no virtual compression (decompression) rotation torque. However, in practice, this arrangement of the closing position is not conducive to the design of the clutch mechanism. Therefore, when designing the closing pressure, the force is required to act near the eccentric direction of the vertical eccentric shaft sleeve. In this way, the clutch pressure mechanism can act at a relatively small angle to achieve the functional purpose of opening and closing pressure

when acting as a force in the eccentric direction of the vertical eccentric sleeve, the eccentric shaft sleeve gets the maximum pressure release torque during printing, and the greater the eccentricity, the greater the pressure release torque, which requires a more reliable pressure closing self-locking mechanism

2) stress on three-point support shaft sleeve

the working principle of clutch pressure of three-point support shaft sleeve is: when closing pressure, two rollers a and B increase the total amount of Hainan maritime border trade and are supported on the cylindrical surface of the bearing; When the pressure is released, the rollers a and B are supported in the corresponding two pits

in theory, the force acting on the shaft sleeve will not produce virtual closing (off pressing) torque when pressing and printing. However, in the actual design, considering that the impact of the A and B rollers entering and leaving the two pits is small, the clutch press mechanism rotates at a small functional angle as far as possible, so it is possible to make the A and B rollers support at the edge of the corresponding pit during the press printing. At this time, a small vibration may cause the roller to slide into the pit, and a virtual closing pressure (off pressure) torque will be generated

3) consideration on shaft sleeve design

many problems should be considered in the reasonable design of clutch pressure shaft sleeve, such as mechanism space, drum arrangement, recommended lining, paper thickness, etc. In this paper, the author puts forward the design consideration for virtual closing pressure

due to the functional needs of each mechanism, it is difficult to completely eliminate the trend of virtual closing pressure in design, but it can reduce the trend of virtual closing pressure, so that the closing mechanism can easily self lock. For the eccentric shaft sleeve structure, the eccentricity should be minimized on the premise of ensuring the paper thickness; For the three-point support shaft sleeve structure, the pit width and depth should be minimized on the premise of ensuring the paper thickness. (to be continued)

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