| 摘要 |
<p>The advance of a tool toward a workpiece is controlled with two acoustic transducers, one acting as a transmitter and the other as a receiver. The acoustic energy transmitted from the one to the other as the tool and the workpiece approach one another (this continuing until contact between the two elements) is detected and used to control a reduction in the speed of approach. The acoustic energy may be transmitted at a predetermined frequency, modulated or characterized in another manner.</p> |
