Importance

Loading Importance Indicators...

Abstract

A feed arrangement for a typing ribbon and/or a correction ribbon comprises a linear motor having a coil-carrying slide which is movable with an alternating rectilinear movement, a toothed wheel for the feed movement of the ribbon, and a connecting mechanism interposed between the coil-carrying slide and the wheel for converting the movement of the slide into a unidirectional rotary movement of the wheel for advancing the ribbon. The connecting mechanism comprises a first lever which is moved by the slide and two mutually independent ratchet assemblies and which are capable of alternately engaging with two diametrally oppositely disposed teeth on the toothed wheel. The ribbon is carried by a cassette and the wheel rotates a blade capable of engaging into a seat in a feed roller of the cassette. The linear motor is of the type comprising a permanent magnet of cylindrical shape, a ferromagnetic core which is coaxial with respect to the magnet and which surrounds the permanent magnet and defines a radial air gap with the permanent magnet, and a winding which is accommodated in the air gap and is supported by the coil-carrying slide. The slide is capable of bidirectional movement coaxially with respect to the permanent magnet in response to bidirectional excitation currents in the winding, coming from an actuation circuit which in turn is controlled by a central unit of the machine.

Loading the Abstract Image...

First Claim