Hermes Precisa International S.a.

Otto Aebi

A ribbon cassette support is pivotally mounted on the printing head carriage of a typewriter. The support includes driving pawls for driving the cassette hubs and a member selectively disengaging one pawl from one hub to allow driving of the other hub by the other pawl in a direction to wind on the ribbon. When the ribbon is fully wound out from said one hub, the continuing action of the driving pawl on the other hug tips the cassette support to a new position in which the control member engages said one pawl and disengages the other, thereby reversing the direction of drive of the ribbon. The cassette support and control member are connected by a spring simultaneously biasing both the support and the member into one of two stable positions.

Typewriter ribbon conveying mechanism

The typist sets a scale to the desired length of paper to be introduced, thereby determining the angle through which a toothed third wheel rotates. Depression of the automatic loading key opens the paper bail and couples the third wheel to a driven toothed first wheel and to a toothed second wheel, which latter turns the platen. The third wheel turns until a finger thereon operates on mechanical linkage to uncouple the three wheels and disconnect the first wheel from the motor. When the automatic ejection key is depressed, the second wheel is meshed with the first wheel, which is coupled to the motor as long as the key is held down, thereby rotating the platen.

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Yverdon, Switzerland

Otto Aebi