| 摘要 |
<p>The machine drives three rail detectors (9, 10, 11) carrying, respectively, a light-beam emitter (13), a screen (15) and a receiver (17) with a photo-sensitive sensor (18) capable of detecting misalignment of the three centres (O, X, Y) of these three elements. In the receiver, the photo-sensitive sensor (18) is moved by means of a motor (22), controlled by its own spacing signal, in order to keep its centre (Y) in line with the centres (O, X) of the emitter and of the screen, a signal measuring this movement being delivered by a movement sensor (28). A signal summer (32), connected to the two sensors (18, 28), delivers a measurement signal (S) which is a function of the difference in level or of the deflection of the track which is the subject of the detection operation, proportional to the algebraic sum of the momentary movement of the photo-sensitive sensor (18) and of the residual momentary lack of centring of the centre (Y) of the photo-sensitive sensor. <IMAGE></p> |
