US 4,059,213 AGranted

Clutchless paper advance mechanism

AssigneeHewlett-Packard Company

InventorTimothy L. Toomay

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Abstract

The paper advance mechanism disclosed herein comprises two essentially identical paper-engaging devices, one fixed, one driven, which cooperate to incrementally advance the paper in a hand-held printing calculator. Each device includes a tapered cavity enclosing a roller which engages the paper as it passes therethrough. The position of the roller in the cavity determines whether that device slidably or non-slidably engages the paper and the position of the roller is determined by the movement of the paper itself. The paper-engaging devices alternately non-slidably engage the paper; when the driven device moves in one direction, it non-slidably engages and thus advances the paper as it moves, and the paper slides through the fixed device; when the driven device reverses direction, it slidably engages the paper as it returns to the start of its travel and the fixed device non-slidably engages the paper to hold the advanced paper in position.

Claims10

Dependent claims

Apparatus for advancing paper along a guide path, said apparatus comprising:

first paper-engaging means, non-rotatably mounted for translation along the guide path including a roller, said roller being responsive to movement of the means in a first direction relative to the paper for non-slidably gripping the paper and for advancing the paper in the first direction, and to movement of the means in a second direction relative to the paper for rollably engaging the paper;
drive means coupled to the first paper-engaging device for moving that device in the first and second directions;
and
second paper-engaging means non-rotatably and fixedly mounted in the guide path and including a roller, said roller being responsive to movement of the paper in the first direction for rollably engaging the paper, and to movement of the paper in the second direction for non-slidably gripping the paper and for preventing movement of the paper in the second direction when the first paper-engaging means is moving in that direction;
said second paper-engaging means including means for releasing its non-slidable grip with the paper when the force tending to cause the paper to move in the second direction exceeds a first value.

2 more elements

Dependencies are inferred from the claim text.