Injection moulding tool, especially for making optical data discs, has ring between tool sections moved by piston cylinder units that apply less force as these sections get closer to each other

摘要

The ring between the tool sections (2, 3) is moved in the tool opening direction by fluid operating piston cylinder units that apply less force to the ring as the tool sections get closer to each other. An injection moulding tool (1) comprises two tool sections defining the mould cavity, one of the tool sections being provided with a ring that surrounds the cavity and can be moved relative to the section in the tool opening/closing direction. The means provided for moving the ring in the tool opening direction comprise fluid operating piston-cylinder units. The fluid operating system is designed to move the ring in the opening direction with relatively great force when the tool sections are spaced apart, but applies less force to the ring as the tool sections get closer to each other. An independent claim is also included for a mould tool section provided with the above piston-cylinder system.