Series 834 Rollmatic mechanical expansion chuck

Vorwald series 834 Rollmatic mechanical expansion chuck

The Vorwald series 834 expansion chuck is suitable for unwinders without shafts. The clamping leaves expand centrically. 
The roughened and hardened surface of the steel leaves allows maximum possible torque transmission when using cardboard, steel and plastic cores.
The functional principle relies on the use of an inclined plane in the winding direction. Due to the web tension of the winding material, a torque acts on the expansion chuck via the reel diameter. This torque causes cylindrical rollers to run up an inclined plane inside the expansion chuck, pressing the expansion leaves outwards. No additional medium – such as compressed air – is required for activation.

The clamping force of the expansion chuck varies depending on the web tension level and the braking torque of the unwinding machine. It is important to note that both expansion chucks must be braked and that a minimum torque of 0.05 x the reel weight acts on the expansion chucks. Another very important advantage of this arrangement is that the clamping of the cores is perfectly centred, as all expansion leaves expand evenly. This enables very high winding speeds to be achieved.
The expansion chucks are based on the Vorwald standard and are custom-made using a modular concept.

Options

• Flange or bearing shaft according to customer requirements
• Special dimensions are available on request

Benefits

• Transmission of the highest possible torques
• Radial run-out accuracy: +/- 0.1 mm
• Quick clamping and unclamping
• No additional medium required for expansion, e.g. compressed air