Method and device for coupling a cassette supported typewheel to a typewheel positioning shaft in typewriters or similar machines

摘要

A method for automatically coupling a typewheel rotatably mounted in a cassette to a typewheel positioning shaft. After the insertion of the typewheel supporting cassette into a typewriter or printer, a coupling sequence is initiated under the control of a microprocessor. During the coupling sequence the typewheel positioning motor is driven to turn a clutch part first in one and then in another direction by a certain angle causing coupling projections on the clutch part to engage corresponding coupling slots on the typewheel. During the coupling sequence, the typewheel is prevented from co-rotating unintentionally due to its moment of inertia and due to active frictional forces.