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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Robert Miehle (1860-1932), a pressman from Chicago, USA, patented an improvement to the Two-Revolution principle in 1884. This was a crank-like device attached to the side of the continuously rotating bed driving gear. At the near end of each stroke the crank enclosed within the walls of a vertical guideway formed at each end of the rack supporting frame, passed through the length of this guide and brought the bed to rest - then returned it with an accelerating motion in proper sequence with the opposing bed rack.. This solved the problem earlier machines suffered with the ever increasing need for speed -- excessive vibration, noise, cylinders moving out of sequence with the bed racks and continual maintenance.
The Two - Revolution principle was invented and patented by a Scot, David Napier, (1785-1873) in 1830. The impression cylinder had a circumference the same length of the type bed (only half the diameter of the 'single revolution'), thus enabling the press to have a lower profile -- a definite advantage to operators!
At the completion of the printing stroke, the cylinder lifted slightly to enable the forme to return under it. One distinct advantage of the two-revolution press was the printed sheet was delivered face up from the impression cylinder, thus negating the problem of slurring/marking caused by take-off cylinders. The Miehle became very popular worldwide due to its simple but rugged construction. Many of these presses were still operating well into the latter half of the 20th century.
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