摘要 |
A drive system for the conversion of a rotary motion into a linear motion contains a belt drive similar to a block and pulley system, and a system of a rack and pinion that is driven synchronously with the belt drive. The pinion and the rack are adjusted with respect to each other such that the teeth of the pinion engage with relatively large play in the rack. When driving under normal load, the drive takes place without loading of the rack and pinion system by the belt drive, so that the reversal backlash and the play of the rack and pinion system remain without effect on the displacement motion. When an overloading of the moving part and a corresponding stretching of the drive belt occur, the tooth flanks of the pinion and of the rack are supported against each other and in this manner prevent tearing or overloading of the drive belt. The drive system has a high reproducibility and a small reversal back-lash, and is particularly applicable for the drive of the focusing motion in microscopes with automatic repositioning by means of a drive motor. |