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The pantograph of Heron (1st c. A.D.) – The first device of copy, enlargement and diminution of drawings

It was an impressive instrument used for copying drawings and figures with the possibility of reduction or enlargement.
It consisted of a plane base with two connected toothed wheels (with the possibility of rotation around a single axle which went through their common centre) and two parallel toothed rulers (that were always in contact with the toothed wheels sliding inside two grooved rods). The latter were transversely connected on one arm rotating round the centre of the toothed wheels. Two rods soldered perpendicularly at the end of the two toothed rulers had, at their ends, the reading pointer and the copy writer aligned with the centre of the toothed wheels. When the operator of the instrument followed the outline of the drawing with the reading pointer, the copy writer drew the copy in scale proportional to the ratio of the cogwheels.

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