Ideal supplement to model #270
power transmission: The draw key is pressed down. This causes the balls to role into the tooth space and act as a fitting connection between transmission input/primary shaft and toothed wheel. idle gear: When the draw key is pulled up, the balls are pressed inward by the tooth space. The toothed wheel has no more connection to the transmission input shaft. Notation: The draw key can easily be moved from the outside by means of a small cam and lever.