Swing cylinder press

The swing cylinder press is a special type of letterpress printing press . According to the functional principle, it is a flat-forming machine with a horizontal pressure foundation .

Structure and working principle

Oscillating cylinder machines are characterized by a very simple structure and trouble-free and low-maintenance operation. The pressure cylinder with a simple circumference is constantly connected to the foundation via a tooth system. The foundation is moved back and forth via a crank mechanism and makes a movement similar to that of a stop cylinder machine . The cylinder swings back and forth synchronously with the foundation. The kinematic principle is a forced, periodic pendulum movement (sine function). In contrast to stop or hold cylinder machines and two-cycle machines, the cylinder also performs a backward movement in each printing cycle.

Depending on the design, the sheet is applied to the cylinder from above (e.g. Salmson Ranger) or from below (e.g. Victoria Front) and is typically removed with the printed side facing up. As a result, the fresh print image was particularly well protected from smearing and scratching. The vibrating cylinder machine places the sheet exactly at the reversal point (i.e. movement-free) and usually transfers it from the table to the gripper using a suction rod. The sheet travel is very smooth and does not smear.

The output of vibrating cylinder presses is between 1000 and 5000 Bg / h. A further increase is not advisable because of the typical double reversal of the direction of rotation per cycle and the resulting mass acceleration.

The grammage is open arc path for almost unlimited to 300 g / m be increased. The weight of an oscillating cylinder machine is similar to that of a stop cylinder machine of the same type. The inking unit was or is typically an inking unit with 6–7 distributor rollers.

Designs and models

Probably the best-known model is the Victoria-Front model, which has been built by Rockstroh AG in Heidenau near Dresden since the early 1930s . The machine was built in three format versions: Gnom , Gudrun SB (800 × 500) and Gerda (1040 × 800). All three versions have the same basic structure and the same functional elements. In the Gerda version, the separately driven compressors were often set up separately in order to keep noise pollution down. The most widespread version was the Gudrun SB , which ran as a punch in many smaller companies until after 1990.

known models: Gnom, Gudrun, Gerda (Rockstroh AG / D, VEB Polygraph / DDR), The Salmson Ranger (GB)

Example VICTORIA front series

Manufacturer formerly Rockstroh AG Heidenau / Sa. subsequently VEB Polygraph Victoria Heidenau / Sa. today Victoria GmBH Coswig and PLANETA / KBA AG Radebeul

Using the example of the GUDRUN type machines, which are still most frequently represented, the schematic structure of an oscillating cylinder press should be illustrated.

The arch system starts at a suction bar with tilting at the right end of the operator's side. The sheet is fed face-down across the table (classic single sheet feeder ). It is guided by ribbons on a metal table. The crank wheel and the simple push rod are located under the table. The direction of rotation of the drive is clockwise (flywheel) and left (crank wheel) from the operator. The air pump (double piston pump) works separately and has its own, cam-controlled switching block for suction and blowing air. The drive takes place via a button-controlled contactor system with a slip ring motor (approx. 3.5 kW). The speed is regulated by a resistance system. The arch system takes place at the bottom of the cylinder, while the pressure foundation comes to a stop on the right. The entry takes place in the front lays , which then swivel upwards. The side pull tabs can be rearranged and the pulling force and width can be very finely adjusted. After aligning, the transfer rod sucks the sheet and swivels it into the stationary gripper . When the foundation moves back to the left, the lifting mechanism (special feature of the oscillating cylinder machines) lowers the cylinder approx. 3 mm and places it in the printing position. When printing, the sheet goes around the cylinder (to the bottom left, then to the top right) and onto the forks. There the grippers open and the sheet is pulled off the cylinder by the discharge belts. Meanwhile, the cylinder goes back with the foundation (in the lifted state = without pressure) to take over a new arch. The shape is colored when the foundation is extended to the left and a second time when it is retracted to take over the arch. The disadvantage of this functional principle is that the inking unit and cylinder also carry out the vibration of the foundation. Due to the periodic reversal of the direction of rotation, the paint is triturated at different speeds. The tendency towards stencils should not be underestimated with these inking units.

The undeniable advantage of these machines was and is the very accessible sheet feeder and the perfect observation of the sheet travel / print. Yet, at the Victoria Front is added that the arc path is long and very the sheet is discharged without contact, so that even strong color jobs well chip off can.

The display takes place face-up on a display board (up to max. 1000Bg. 80 g / m²) or on the removable high pile delivery (up to approx. 5000Bg. 80 g / m²).

Known locations

In the Stiftung Druckkunst in Leipzig a "Gudrun SB" (Bj. 1939, Rockstroh AG) and a "Gerda" (VEB Polygraph), both fully functional and in operation

in the Dornbirn printing works (Austria) a "Gudrun SB" from the VEB Polygraph Viktoria, with high pile delivery (partially functional, not in operation)

on the Dishley farm near Rostock a "Gudrun SB" (b.1963) from VEB Polygraph Viktoria, construction number 7104, with high pile delivery (partially functional, in restoration)